rough idle, throttle unresponsive when cold

Is this the drive cycle you're talking about?

1) Begin drive cycle by starting the vehicle and let idle for 15 seconds.

2) Cruise at 40mph for 4 minuites. Bring vehicle to a stop.

3) Cruise between 45mph to 65mph for 10 minutes. Bring vehicle to a stop.

4) Drive in stop and go traffic condition. Include five different cruise speeds
ranging from 25mph to 45mph for 10 minutes. Bring vehicle to a stop.

5) From a stop, smoothly speed up to 45mph. Slow to a stop.

6) Repeat step 5

7) Repeat step 5

8) Idle in Drive position for 2 minutes.

9) In Overdrive position, Slowly cruise to 50mph for 15 seconds then bring vehicle to a stop.

10) In Normal position, Slowly cruise to 40mph for 30 seconds. Continue...

11) While in 40mph cruise, shift to Overdrive and speed up to 50mph
cruise for 15 seconds, then bring the vehicle to a stop.

12) Repeat step 9
13) Repeat step 10
14) Repeat step 11

15) Repeat step 9
16) Repeat step 10
17) Repeat step 11

18) Repeat step 9
19) Repeat step 10
20) Repeat step 11

21) Repeat step 9
22) Repeat step 10
23) Repeat step 11

24) Repeat step 9
25) Repeat step 10
26) Repeat step 11

27) From a stop, Cruise to 65mph, let off the gas - no brakes, slow down to 40mph. Continue...

28) From 40mph, Cruise to 65mph, let off the gas - no brakes, slow to 40mph.

29) Repeat step 28, then bring vehicle to a stop

End of Drive Cycle

youre in the ballpark with that; check the top of that page in the manual because there are certain conditions in which the steps need to be performed. and dont forget that there is a process for just the battery that needs to be completed before you do all that. the battery process is in the owners manual
 
Back to "calibrating" the LS again, I see.

<shrugs>

beats the "spend $1000 and break a bunch of s h it that may not even be broken" advice that has been pushed his way thus far.
 
I got two coils replaced under warranty, bought 6, bought all new plugs (Motorcraft plats), MAF sensor cleaner and TB cleaner, and Lucas fuel treatment.

I found all kinds of issues during my work today.

1) MAF sensor wire was literally covered in oil and grime. I had never treated this part before. A few bursts of CRC MAF cleaner and the wire and red sensor was bright and clean. I also blew out my K&N panel with compressed air and saw no signs of excessive oil.
2) TB was pretty bad. (pic 1) Cleaned thoroughly with CRC TB cleaner
3) A few of the plugs were baked pretty good, and had a good bit of oil at the threads but not on the electrode or ceramic insulator (pic 2). No oil or moisture in wells at all (thank god). Btw I posted this earlier in this thread but the VCG's were replaced 18 months ago. The new gaskets are doing their job.
1) All the old plugs had a .048" to .054" gap (pic 3). New plugs were gapped properly at .041"
3) Clip/connectors on two of the coils were broke. They were still seated but the clicky thing wasn't engaging. When reconnecting the coil connectors, they all got a good smear of grey RTV across the clips to hold them together securely.

After I got everything put back together I drove her for about 20 miles, making sure to get shift points learned without any WOT. I will probably try to take her easy for another 60 miles or so, but so far the drive is fine.

dirty throttle plate
20130303_155450_zpsb2693716.jpg


old plug
20130303_165131_zps6fae08f1.jpg


old gap
20130303_165855_zpsc5ab8a0a.jpg


new gap
20130303_172924_zpsc2d6e458.jpg
 
I've only started her twice since getting everything back together - the very first start after re-connecting the battery, the idle was a bit rough, but of course the computer had just been reset, so I'd expect it to be a bit wonky. I let it idle for about 2 minutes then started it again and the idle was noticeably smoother. Drove her home about 20 miles nice and easy, some stop and go, some steady cruising at 40-50, and some highway driving. Poured a small bottle of Lucas in the tank and topped it off with 93.

I'll let you know how things feel in the morning, supposed to be in the low 50's which normally would be cold enough to be a problem.
 
I find it rather odd how you weren't getting any CEL's on the dash, specifically with the MAF sensor all gunked up.
and even with a misfire like that you should have had a blinking CEL under WOT, which clears codes during the same drive cycle.
Only way to read a PO3XXX misfire is to WOT until it's hitting the spot where it misfires, CEL blinks, pull over immediately and read the code.

Next time you clean and oil the K&N filter, clean it well, let it dry properly and don't over oil.
More so then not this refreshing of the K&N filter is done incorrect and it tends to get over oiled while still wet and it gets into the sensor element of the MAF.

You'll always be told you need a new MAF but a simple gentle cleaning is usually all it takes.

Anyhow, glad to hear/see you got on it with the fixing and spotted a lot of issues as you discovered.

The rotten egg, sulfur smell, might still be there under WOT, need some CATS later on, as they've been overworked with raw fuel for some time.

+1 on working on it and getting it done!
 
Over oiling after market filters can cause all sorts of issues. Yank that filter out, use some good intake/map sensor cleaner and put in a quality stock type filter.
 
Over oiling after market filters can cause all sorts of issues. Yank that filter out, use some good intake/map sensor cleaner and put in a quality stock type filter.

I've had an oiled filter on two separate LSes for well over 150K miles. As long as they are cleaned and oiled correctly they are well worth installing. I haven't ever had an issue.
 
1) MAF sensor wire was literally covered in oil and grime. I had never treated this part before. A few bursts of CRC MAF cleaner and the wire and red sensor was bright and clean. I also blew out my K&N panel with compressed air and saw no signs of excessive oil.

Do not use compressed air on a K&N filter! It is very very easy to blow holes through the material. To clean, you just spray with the cleaner and pour water through it, then let dry.

3) Clip/connectors on two of the coils were broke. They were still seated but the clicky thing wasn't engaging. When reconnecting the coil connectors, they all got a good smear of grey RTV across the clips to hold them together securely.

Next time around just use some zip ties. The RTV won't help and will make a mess.
 
Do not use compressed air on a K&N filter! It is very very easy to blow holes through the material. To clean, you just spray with the cleaner and pour water through it, then let dry.



Next time around just use some zip ties. The RTV won't help and will make a mess.

Thanks for the tips. I used compressed air about 6-8" away from the filter just to see if I could get any spatter of oil to the other side, which I didn't. It was in no means a method for cleaning the filter, as it was already very clean. The RTV seemed to be holding them fine, the connectors were not coming apart with moderate yanking. But the zip ties are a good idea. Thanks again.
 
Be careful not to get RTV on the contacts. Some formulas of RTV will corrode copper.
 
Ultra Grey RTV Silicone:

Features:
Designed specially for high-torque and high vibration applications

Exceeds manufacturers' performance requirements

Non-corrosive, low-odor gasket maker is guaranteed not to leak

Suggested Applications: Valve covers, oil pans, intake manifold end seals, timing covers, water pumps, thermostat housings.
 
Overall it's running a bit better for you now Stump ?
 
What I've driven so far (about 40 miles) has been running well. The start-up and reversing out of my drive this morning was smooth.
 
Car backed up a little jerky this morning, but the throttle was responsive in park. After driving for a minute it ran normal. I don't think I fully nailed this issue yet, but am done throwing hundreds of dollars at an issue that may or may not give me 30-90 seconds of grief every other day.
 
Up to the normal behavior still. Maybe a little "less bad". Any ideas what to check next?
 
No CEL at all ?

Stock air intake plenum, no cracks anywhere ?

Plenum silencer cracked underneath ?

All torque screws on top of the MAF housing tight ? (one of mine was done)

Sure there isn't a vacuum leak somewhere ?
 
Crap fuel?
Water in tank?
Always fill up at the same place?



Although I expect my numbers to start falling soon because I can feel a problem with at least one COP coming on, I am averaging 19.8-20.3mpg using 92. During the summer I was getting about 22. My daily drive averages somewhere around 40/60 (city/hwy.) The brand of fuel I use can have a noticeable different as can certain stations no matter the brand.

A long time ago I had a loaded Taurus and that car was VERY sensitive to what I fed it. Chevron was king, followed by Shell and Exxon. BP rated with the local brands, and it absolutely HATED, as have all my cars, ARCO (aka AM/PM Stations around here)... I only made that mistake once and even then it was because I had no choice. But she damn sure she made me pay for it throughout the whole tank (time decreased some, by diluting it with good stuff)
 
No CEL's.

I don't know how to check for cracks in the air intake plenum/silencer (other than visually), and I haven't had a vacuum test done by a professional. I will be doing that in a couple weeks, though.

MAF is tightened down good, and has been cleaned and inspected.

Fuel is 93 octane from Chevron for the past month, two different locations. (Although, I'm ruling out fuel because I've had this issue for the past 4 months with all different brands). Fuel filter is ~18mo/15000mi old. Will also be testing fuel pressure when I have the PCV tested.
 
Yesterday I had some Michelin's put on the front wheels, and when the shop guy was putting my spare and jack back in the trunk, he noticed my battery was not secured with the bracket, and that was because the battery was the wrong size (too small). Anyways, he told me I should get it replaced with one of the right size. So anyways, getting a pretty serious audio system put together in the LS, I've had a new Kinetik AGM battery sitting in my garage with my other equipment for the past couple weeks and decided to install it this morning. Fits like a glove, a very tight glove. Upon starting after installation, I did not get any stuttering or rough idle I am used to. It may have been a fluke, but could this have been a voltage issue in any way?

20130315_113227_zps829837c7.jpg
 
The big plastic cap that you stuck on the end of the battery hold down actually goes on the end of the spare tire hold down. It's purpose is to give support to the middle of the trunk floor panel.
 
LOL ... now that's funny.

RE: "Upon starting after installation (battery), I did not get any stuttering or rough idle I am used to.
It may have been a fluke, but could this have been a voltage issue in any way?"

May very well be, we all know that when disconnecting the battery for a period of time,
on re-installation it needs to relearn the idle air mixture rate and such.
It will do this on it's very own.

By checking the air intake plenum I meant check the underneath side of the silencer right at the front on top
of the radiator. I've seen someone post a pic here where the underneath side had a crack along the seam.
I had looked for the picture but couldn't find it.

Hopefully this will be the end of your troubles.

Although we tend to give member "jrand" a hard time about his recalibrating procedures, when disconnecting
batteries, there is some truth to it, only it's suggested the LS does it on it's own during a few drive cycles.

It's in the shop manuals for the reason for the tech to have it done by the time customers pick their cars up
and to ensure during test drives, all problems are resolved.
 
Yea youre probably right. I almost expect the issue to come back after a couple startups.

The silencer has no cracks in it. I cleaned and inspected it thoroughly when I did the work outlined in this thread on March 3rd. I didn't know that's what that thing was called! :p
 
I read that on a thread here somewhere long time ago, looked for it, can't find it again.
the picture had a red hand drawn outline around the extra chamber on the plenum.
 
It figures, I was looking at it from all angles like "Well That's Fantastic (WTF) is the point of this thing?" It does look like something to choke the intake of air a bit in order to eliminate resonance or something. joe, you have any idea what purpose it might serve?
 

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