'05 LS V6 - Sputtering & Running Rough @ Highway Speeds

[Eurythmian]

I was wondering if other '05 V6 LS owners have ever had this issue or heard of one doing this.

It just started doing this with Texas heat getting up to 100˚. I don't know if the heat has anything to do with it... but it has done this twice when it has been really horribly hot out.

I've been cruising along with the cruise control activated at 70 mph and touched my brakes to deactivate the cruise control - then the car seems to choke and sputter - loosing all power while running extremely rough. The wrench warning light is then lit. I pull over and shut everything off ASAP. Sit for a few seconds then start the car. Everything seems to be OK.

I just had the car serviced at a FORD/Lincoln Mercury Dealership and after having the intake manifold cleaned they told me everything checked out to be perfect... just needs some new brake pads in the near future. The car is super well maintained and I've only had a window motor go out and the manifold cleaning issue thus far. I am the cars second owner.

I experienced this issue once a week ago. I thought maybe it was due to a dirty air filter because it was time to have my K&N filter cleaned - it was right at a year since I put it in and K&N recommend cleaning every 12 months. I cleaned the filter this past Saturday and found that cleaning twice a year is probably a better plan. The filter was so dirty it looked like my kids had used it in a sand box. That was shocking! Now that it's clean, the car has so much more HP/get up and go it's amazing. Thinking I had maybe solved this sputtering issue, I was worry free.

UNTIL TODAY - it's 100˚ outside again and it did this same exact thing when I tapped my break to deactivate the cruise. I pulled over shutting everything off. Sat for 5 seconds - then started the car and it ran fine the rest of the day.

Hope someone has had this issue so I can point the dealership in the correct direction. It's still under warranty... just a pain to have to deal with it.

Thanks for your help.

 

[Andrizzle]

Hmmm. Are you aware of the last time your coils or plugs were replaced?

 

[pektel]

johnson rod.

 

[joegr]

You may want to forget the warranty and just go ahead and change all six coils and plugs yourself. This is the least grief approach, and I promise it will fix the issue.

Alternately, you can go to the dealer. If they are not very experienced with the LS, they will want to change out the throttle body and/or the gas pedal assembly. This won't fix it.

 

[milehighmikey]

I'm thinking that coils go bad and stay bad, so this car doesn't really do that.

When reading the description in real time, it seems like the engine is going into limp home/ emergency cooling mode and disabling half of his engine. The condition could be based on one faulty sensor reading or possibly due to an air pocket near the temperature sensor of the engine.

Can you get the codes dumped from the engine computer after this happens and look at what they mean? Go to an auto parts store that dumps codes for free and stay away from your dealer until you have a definite indictment on the real problem.

The dirty intake manifold cleaning seems to be a great way to pull in some easy money. They all get dirty inside due to oil fumes being brought into the engine through that path and normal engine operation.

 

[joegr]

I'm thinking that coils go bad and stay bad, so this car doesn't really do that...

You obviously don't know the gen II LS well, don't understand the effects of RFI, and don't know about internal high voltage breakdown of the coils.

The epoxy insulation in the coil starts to fail.

The coil starts to experience high voltage breakdown. This is when a spark arcs inside the coil, either instead of at the sparkplug gap or in addition to it.

This arcing in the coil causes radio frequency interference.

The RFI is picked up by the sensitive circuits of the throttle by wire system.

The PCM sees the noise in the throttle circuits and reduces the engine to idle only. This is when the wrench light comes on on a V6, or you get an ETC message on the V8.

Turn the engine off, and the failure mode is cleared. It comes back later when too much noise is picked up from the bad coil(s).

Research it...

 

[n8bachelor]

Let's try the simple things first gentlemen. Coil problems on the v6 are less common than on a v8...but it does happen.

You say you had the problem once prior and that is why you cleaned the filter... was the problem worse after you cleaned it than before? If so I suspect the MAF sensor is dirty. Try cleaning your MAF sensor with some appropriate cleaner and see if the problem persists. Sometimes you can get too much oil on the filter and dirty up the MAF sensor.

The v6 also have problems with the pcv hose under the intake.... but that is a whole other ball of wax.

 

[joegr]

Let's try the simple things first gentlemen. Coil problems on the v6 are less common than on a v8...but it does happen.

You say you had the problem once prior and that is why you cleaned the filter... was the problem worse after you cleaned it than before? If so I suspect the MAF sensor is dirty. Try cleaning your MAF sensor with some appropriate cleaner and see if the problem persists. Sometimes you can get too much oil on the filter and dirty up the MAF sensor.

The v6 also have problems with the pcv hose under the intake.... but that is a whole other ball of wax.

Good suggestions, but keep in mind that none of those things will turn the wrench light (ETC failure) on. I've now seen this on three or four of the V6's.

 

[Eurythmian]

I had the intake manifold cleaned because it was really bad. I requested seeing it with my own eyes. They took me out to the shop and showed me what they were talking about. The previous owners must have used lower octane gas because I have always used premium fuel. I was also instructed to use a bottle of intake cleaner once a month or so to keep it cleaned out. The difference after they cleaned it was like night and day... feels like I'm driving a different car.

To answer another question, No it did this shuttering before and after I had the manifold cleaned and it was the same each times - acted exactly the same.

It also had an oil leak in the intake manifold. Something to do with a valve which shifts back and forth depending on your acceleration. You will need to excuse my ignorance with mechanics... I'm far from savvy when it comes to this kind of thing. I'm a graphic artist - not a mechanic. But, I do have a mechanic who I have used for years and I trust... he wouldn't do me wrong. But if any of this is covered by the warranty I will probably take it to the dealer to keep it all official.

So I it sounds like what I need to do is start with the coil pack and plugs. Would the wires needs to be replaced at the same time since I'm doing all of this? Is this something I can do myself? Would I need any special tools if I did it myself - and what is the location of the coil pack on gen II V6? I have changed plugs and wires on several cars in the past... I know I can do that. LOL

This really sounds like what I need to do. When this happens, the car does exactly what JoeGr said it would do... it goes into idle mode.
Fells like it's hardly running and the engine is shaking pretty hard. Then it's back to normal after I shut it down and restart it.

Thanks for your help guys... this sight is invaluable with the info I have learned here.

 

[joegr]

I had the intake manifold cleaned because it was really bad. I requested seeing it with my own eyes. They took me out to the shop and showed me what they were talking about. The previous owners must have used lower octane gas because I have always used premium fuel. I was also instructed to use a bottle of intake cleaner once a month or so to keep it cleaned out.

It also had an oil leak in the intake manifold. Something to do with a valve which shifts back and forth depending on your acceleration. You will need to excuse my ignorance with mechanics... I'm far from savvy when it comes to this kind of thing. I have a mechanic who I have used for years and I trust... he wouldn't do me wrong. But if any of this is covered by the warranty I will probably take it to the dealer to keep it all official.

So I it sounds like what I need to do is start with the coil and plugs. Would the wires needs to be replaced since I'm doing this? Is this something I can do myself? Would I need any special tools - and what is the location of the coil on gen II V6? I have changed plugs and wires on several cars in the past... I know I can do that. LOL This really sounds like what I need to do. When this happens, the car does exactly what JoeGr said it would do... it goes into idle mode. Fells like it's hardly running and the engine is shaking pretty hard.

Thanks for your help guys... this sight is invaluable with the info I have learned here.

Your car has six coils (one on top of each spark plug), and no spark plug wires. The oil leak may have been from one of the two VCT solenoids that control the valve timing.

A lot of gunk in the manifold is a bad sign. You may have excessive blow by due to worn rings (expensive), or maybe your PCV valve is bad (cheap).

You are out of factory warranty. Do you have an extended warranty of some sort? (Ford did extend the coil warranty to 100K for gen II V8s, but only for the V8s.)

 

[Eurythmian]

I do have an extended warranty. They have been really good about covering several of the cars issues every time I have needed these things done. The manifold cleaning did cost me $175.00. I was probably ripped off I know... but I was there and they had my car and yes it was pretty pathetic. It runs so much better and my gas milage has almost doubled.

Oh, when they fixed the oil leak in the intake, (bad O-ring or something like that) they replaced the PCV hose and valve.

The coil and plug thing sounds very weird... I'm use to plugs and wires. Are they difficult to change out? Would I need any special tools? You always need a special tool when working on newer cars it seems...

 

[joegr]

I do have an extended warranty. They have been really good about covering several of the cars issues every time I have needed these things done. The manifold cleaning did cost me $175.00. I was probably ripped off I know... but I was there and they had my car and yes it was pretty pathetic. It runs so much better and my gas milage has almost doubled.

Oh, when they fixed the oil leak in the intake, (bad O-ring or something like that) they replaced the PCV hose and valve.

The coil and plug thing sounds very weird... I'm use to plugs and wires. Are they difficult to change out? Would I need any special tools? You always need a special tool when working on newer cars it seems...

No special tools. It's a pain on the V6 because the upper half of the intake manifold has to come off to get to half of the plugs and coils.

COP (Coil on Plug) is the norm these days, and has been for several years now. I doubt that any car comes with a single coil and a distributor anymore. Similarly, throttle by wire is very common now too. Times change...

 

[Eurythmian]

Well my last car was a 1994 Lincoln Mark VIII. You could actually work on those. The rest of my cars have all been newer with warranties and I let the dealerships do it all.

Thanks for all your help... I will let you guys know what the outcome is.

If anyone has any other suggestions - please post.

 

[milehighmikey]

You obviously don't know the gen II LS well, don't understand the effects of RFI, and don't know about internal high voltage breakdown of the coils.

The epoxy insulation in the coil starts to fail.

The coil starts to experience high voltage breakdown. This is when a spark arcs inside the coil, either instead of at the sparkplug gap or in addition to it.

This arcing in the coil causes radio frequency interference.

The RFI is picked up by the sensitive circuits of the throttle by wire system.

The PCM sees the noise in the throttle circuits and reduces the engine to idle only. This is when the wrench light comes on on a V6, or you get an ETC message on the V8.

Turn the engine off, and the failure mode is cleared. It comes back later when too much noise is picked up from the bad coil(s).

Research it...

Thanks joegr. I had no idea of this and it does sound plausible. Does any of this stuff get logged? Sounds simple to confirm, if it does get logged.

As for the dirty intake, and your fuel economy nearly doubling, what are the numbers we are talking about in terms of MPGs?

 

[joegr]

Thanks joegr. I had no idea of this and it does sound plausible. Does any of this stuff get logged? Sounds simple to confirm, if it does get logged.
...

Trouble codes will be logged for either the throttle body, the gas pedal, or both. On the 03's, if just throttle body codes are logged, it actually is a throttle body defect about half the time. On the 04s and up (or the 03s if a gas pedal code is logged too) it is almost always caused by a defective coil.

I'm too lazy to look up the codes now, but they've been posted here a number of times.

 

[milehighmikey]

I appreciate your willingness to help out, but looking up codes or reading code to see what can get logged would be far beyond the call here. I just wondered if the codes would get logged and if they did, that would help lead to the problem. Overall, if a car could do what the OP's does and nothing got logged, that would be a real pain to troubleshoot. The way his description of the problem and the resulting only fix the garage could do, seemed to indicate that this was a transient, completely phantom problem, and made me wonder if anything got logged.

I'm still awaiting those phenomenal MPG improvement numbers.

 

[Eurythmian]

I'm still awaiting those phenomenal MPG improvement numbers.

OK maybe MPG doubling was a bit too much. I can only tell you I would fill up on Sunday from being empty and was needing to fill it back up on Tuesday after work. I knew something was not quite right because my Mark VIII never drank gas like that.

I need to actually calculate my milage... but going by the same scale and drive a much further distance per week because of a new job, I top it off Sunday and I can make it until the following Thursday after work with a quarter of a tank still to go. I'm quite pleased with the improvement.

I have a scheduled appointment with Lincoln Mercury in the morning. I will post my results.

Thanks for all your help.

 

[Eurythmian]

OK... the results.

Took it to Don Davis FORD/Lincoln Mercury and they diagnosed it as coils 2, 4 and 6 failing. They only had four coils in stock and it would take a day to get the rest in. I needed the car back today so I told them to replace all six plugs and four of the coils - knowing coils are either good or bad and that they would need to remove the intake manifold to get to the middle and rear plug/coils.

So I requested having the two remaining good coils be moved to the front so I could change them out myself when they die.
They honored my request.

Total cost: $1,035.33 (HOLY JEEEZZZUS!!!!)

Extended Warrant covered the three failed coils and the manifold gasket plus some labor: $683.92.

My cost: $351.41. (1 coil, 6 plugs and some labor)

Thank GOD for my extended warranty! There is quite a difference in the cars performance. And my thought is - there should be! Over $1,000.00 for new plugs and coils... I'm speechless!
:eek2:

 

[Andrizzle]

Sounds like that mechanic got a smokin' deal...

That was probably less than $100 in parts.

 

[Eurythmian]

Sounds like that mechanic got a smokin' deal...

That was probably less than $100 in parts.

I've learned my lesson... never again will I take it to the dealership for warranty work. I have a mechanic I trust and he is really honest.

I have never heard of plugs and coils or wires costing more than 200 bucks. They had to pick me up off the floor. I kept asking them if that price was correct... then I started laughing because I was in shock... completely in shock!

:eek2: :eek2: :eek2: :eek2: :eek2: :eek2: :eek2: :eek2: :eek2: :eek2: :eek2: :eek2: :eek2: :eek2: :eek2: :eek2: :eek2: :eek2: :eek2: :eek2: :eek2: :eek2:

 

[Mechanicboy]

Total cost: $1,035.33 (HOLY JEEEZZZUS!!!!)

Extended Warrant covered the three failed coils and the manifold gasket plus some labor: $683.92.

My cost: $351.41. (1 coil, 6 plugs and some labor)

Thank GOD for my extended warranty! There is quite a difference in the cars performance. And my thought is - there should be! Over $1,000.00 for new plugs and coils... I'm speechless!
:eek2:

That's the stealership for you. I did my coils and plugs for about $150, solved my problem for 99% of the time, but I still have a issue sometimes around 3300-4200 RPM, only when I punch it and not every the time. It feels like it runs lean, so I'm thinking of hooking up a fuel pressure gauge to check it out.

 

[LS4me]

I have never heard of plugs and coils or wires costing more than 200 bucks. They had to pick me up off the floor. I kept asking them if that price was correct... then I started laughing because I was in shock... completely in shock!

Well.......

The plugs are probably $5 apiece (~$30) and the coils are about $50 ($300). The LS doesn't have plug wires. I'll bet the book charge for replacement of the coils/plugs is ~3 hours; there's another roughly $300. Plug changes on the V6 are a bugger.

 

[joegr]

Well.......

The plugs are probably $5 apiece (~$30) and the coils are about $50 ($300). The LS doesn't have plug wires. I'll bet the book charge for replacement of the coils/plugs is ~3 hours; there's another roughly $300. Plug changes on the V6 are a bugger.

I'd say that your estimate is correct.

 

[joegr]

...
So I requested having the two remaining good coils be moved to the front so I could change them out myself when they die.
...

Don't wait, change them out now. It's not worth the risk of destroying a converter. You can get the coils from Max at a good price.

 

[Eurythmian]

Are new coils better built or something? Are the original ones just sh!t? Why would I need to replace them now if they seem to be fine? A read a coil is either bad or good. No need to replace it if it is working. Is this true?