fluctuating idle / misfire problem

Thanks.
So let me clarify:

1. You agree that oil on the boot indicates valve cover gasket leaks (and needs replacement)?

2. Your opinion is: don't change one coil pack, change them all?

(So you would replace the coil packs and the valve cover gaskets?)

*Any tips on vacuum leak tests?
I sprayed some of the lines with starting fluid, noticed nothing...
 
thehamm99 said:
Thanks.
So let me clarify:

1. You agree that oil on the boot indicates valve cover gasket leaks (and needs replacement)?

2. Your opinion is: don't change one coil pack, change them all?

(So you would replace the coil packs and the valve cover gaskets?)
Click to expand...

1. absolutely.

2. yes. unless you can identify which coil (or coils) are faulty, they do make expensive machines that can test for that, you will just be endlessly chasing which of the 8 coils are bad.
 
thehamm99 said:
Thanks.
So let me clarify:

1. You agree that oil on the boot indicates valve cover gasket leaks (and needs replacement)?

2. Your opinion is: don't change one coil pack, change them all?

(So you would replace the coil packs and the valve cover gaskets?)

*Any tips on vacuum leak tests?
I sprayed some of the lines with starting fluid, noticed nothing...
Click to expand...

Change the valve cover gasket
It okay to change one coil BUT change all spark plugs
The valve cover gasket is :q:q:q:q on these cars the oil leaks out to the plugs and coils causeit to misfire or die out clean out all the oil before putting pluggs and coils......... I have the problem with car stalling out only when I turn but its my power steering
 
Okay...

So I ordered 8 new coil packs and valve cover gaskets, and I was hoping they'd get here so I could go through that all on Sunday...

But, in the meantime...

Yesterday and today, on a cold start, the condition has gotten MUCH WORSE.
More pronounced fluctuating idle...hesitating and surging while accelerating, etc.

Would anybody have a guess as to:

1. This is just the same thing that's been wrong getting worse, or
2. The IACV and one coil pack I bought from rock auto brand new and put on the other day could be total garbage and are making the problem worse.

Thanks.
 
Not sure with mod motors but with our engines one bad coil can cause other good coils to fail as well.

Also repeated driving on bad coils can trash your cats, which can cause the engine to run poorly.
 
Last edited:
Well, I guess I'll know for sure this Sunday (if the coils get here).

I'm going to remove the plugs, check for gap, clean out the area that's gotten oil on it.

Swap the valve cover gaskets for new ones

Put in 8 new coil packs and boots (even though I have new boots!)

Then if the problem isn't gone I'll put my OEM IAVC and TPS back on and see if swapping those actually made the previous problem worse.

And if all that fails I'm down to looking into the IMRC and or fuel injection stuff I guess, then taking it in somewhere to get diagnosed.

No check engine light...but would borrowing an OBD2 be a good idea to pull minor codes??
 
Here's my update.

I swapped the original 8 coil packs with Ebay after market ones (with boots and springs).

I regapped the spark plugs and made sure it's all good there...

I didn't venture into replacing the valve cover gasket because on closer inspection I had one minor oil spot on 2 of the boots...nothing too bad, so I decided to hold off on that project.

Here's what happened:

Day 1-1.5

Car ran perfectly. No jumpy idle, seemed great.

Day 2-4 (now): Idle is extremely jumpy on cold starts, but rests pretty much normally when warm (though the engine feels a tiny bit rough in spots, but no jumpy idle).

Before I swapped the coils and the jumpy idle problem was getting worse, I had the feeling that one of the IACV or TPS that I got from Rockauto (cheap kind) might be the culprit, so I'm ready to swap my old ones back on and see what happens...

Has anyone had an IACV or TPS be this crappy right from the get go? (within 2-3 weeks of install)?
 
Hammer, I have a very similar issue. Here's what I've done so far: replaced the intake and IRMC gaskets. I also cleaned the IRMC plates (they were pretty filthy). I wanted to change the O-rings on the IRMC shaft but I couldn't get the screws loose on the blades. I also changed the valve cover gaskets and put in all new COP boots; cleaned the MAF and TB with approved cleaner. I'm on my third IAC but still get a CEL 1506. I haven't been able to find any vacuum leaks and the plugs looked fine. I changed them about 5000 miles ago. My car has almost 170000 on it.Car idles between 800 and 900 RPM when warm but has a vibration to it.
 
Yeah I'm stumped. I'm no expert though so I have no clue.
I put my original IAC back on and same result. Haven't tried putting the original tos back on yet.
Here's what's happening to me:
1- when the car is ice cold, first start of the day: crazy idle jumping between 600-1000, with hesitation on acceleration, and hesitation in engine response.
2- 10 minutes warm, minor fluctuation in idle, minor hesitation and or surge.
3- engine totally warm, idle remains 90% steady, but car feels rough and vibrates, just isn't smooth, and that roughness is evident at all speeds at all times.

I need to determine if there are any vacuum leaks anywhere. Any method better than spraying starting fluid all over?
 
I unplugged all the vaccum ports from what ever they were connected to. I then plugged them and applied vacuum with a hand pump. The guage on my pump showed no loss. However, that doesn't mean the devices the hoses were hooked to were't bleeding vacuum.
 
Okay, so I finally took it to my mechanic. He diagnosed a misfire in cylinders 7 and 8.
He said all the new coils were fine and suspected fuel injector issues. I grabbed a few injectors at pick n pull and swapped 5,6 into 7,8, and put the junk yard grabs into 5,6 (eliminating the injectors that were in 7 and 8).
Ran the car, had the same issues. Also, had tested each injector for voltage...and electrically tested them out of the car by connecting 12 volts and making each injector shoot open and spill gas...even the ones that had been in 7,8 worked this way.
So tomorrow I plan to loosen the fuel rail so I can see if gas shoots through 7,8 when starting, and test the injector electrical hookups for power...

Any other ideas??
 
That was the idea behind moving the injectors.

My guy went out of town and when he comes back i'm supposed to bring it back in, he'll hook it up to his machine and see if the misfires followed those injectors to other cylinders.

I have the 8 original coils and boots as well as an extra new one (in addition to the 8 new ones I put on a month or so ago).

If it's an issue with the coils in 7,8, I'm sure I could find a combination of used coils that would fix that. I don't think that's it, but I'll try that tomorrow.
 
Okay, I've tested the fuel injection, and the coils enough to decide there is no problem with fuel or spark...yet I'm getting a misfire in cyls. 7 and 8.

What could be another source of misfire in those cyls.?
 
Without reading completely through this........


Has anyone mentioned Ohming out the Primary and secondary sides of each coil? I even test them cold and heat soaked.

It's found every bad Ford coil I've ever had.


Mike
 
Okay.

Good news: My mechanic didn't charge me for any tests he did.

Bad news: He's pretty sure I have some messed up valves.

50lbs of loss on cyl, 7, 20 lbs. loss on cylinder 8.

So...opinions,

Is this something that could be carbon/gunk related (and seafoamed to death), or is this amount of loss just too much for that to be possible?

I'm not getting into tearing the engine apart, messing with the timing chains and all that, and I'm not paying someone to do it.

So if the seafoaming option doesn't work, I'm down to either junking the car for a small income, buying a used engine and selling the good parts from my engine, or parting the car out completely then junking it.

Any opinions???

Thanks.
 
I am having these same issues but don't have the money to go have a test done. Let me know if you figure it out please. I will follow this thread also. I feel your pain.
 
I was still trying to figure mine out as the idle is still just a bit off even though it had stopped trowing codes after the latest IAC I tried. I finally said "screw it" and have just be driving it around. Friday night the CEL came back on. This time a code PO430. After doing some reading, most conclude that it would be a catalytic converter and not the O2 sensor. I'm going to pull the exhaust and see if it is stopped up. Others said that could also cause a rough idle. Do you have any sulfur/gas smells from under the car or hear any rattling from the exhaust?
 
No smells or rattles. But you can listen at the intake and hear a thud...a misfire, or backfire...my mechanic seemed confident that it is bad valves in those two cylinders...still don't know what was meant by the "convertors" comment.

I guess my question for anyone who wants to take a crack...does 50 lbs of loss in compression to a cylinder sound too harsh for it to be a "carbon" situation?
 
My "converters stopped up" comment was in relation to my explanation above with my idle issues. It may not pertain to you. Just something else to possibly look into.
 
So, I ended up doing 2 bottles of seafoam through the brake booster, a day apart.

And...its been several days, and what do you know, no more idle issues.

I can still hear a little bit of roughness in the motor, but no hesitation, and no jumpy idle at all.

It is possible that when I first did a seafoam through the pcv a few months ago I knocked some gunk into the area of the valves and it got stuck...maybe.

If the car stays running like it is, knowing I may have some valve damage...eh, I'll take it.
Would be interesting to do another compression test and see the current results.
 
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