Serious stutter stammer problem
 

Well, my car is really pissing me off. I can't figure this out. It started to run poorly. Lobey idle and then heavy missfires when you drive it. This all startd right after washing the engine bay. When you press the gas it stutters and stammers really bad, then it will seem to pull itself out, and then starts doing it again.

I ended up pulling all the plugs and found some condensation in three of them. Also, one plug that looked like it might have been arching. So, I thought I found the problem. Also, I found some crap in some of the plug holes. You know, some grit and grime.

I replaced the plugs, cleaned the coil packs, and cleaned out the plug holes as best as I could. I put her all back together. And took it for a ride. It seemed to be fine, then after only about a mile, the problem came back. This time with a vengence.

Any help would be appreciated. The car is currently not drivable.

Geez Blake. Did you get the filter wet?

Very interesting. I've washed my engine bay several times and never experienced a problem. Have you replaced the Fuel Filter? Maybe it isn't related to the engine cleaning, it might just be oddly coincidental.

Good luck sorting it out,
Philip K.

How soon after washing it down did you drive it? You may have shorted something to ground. Youve must have lost spark or fuel to one or more cylinders. Im sure you have a laptop PC, you have autotap program? Its not a real expensive program if you don't. I would hook up with that and see what codes its throwing if any, what cylinders are miss firing(program can monitor like 8 things at once If I remember correctly. Thats what I would suggest.

www.autotap.com is homepage

Dont think its throwing any codes right? This is why I dont think its a misfire. Could you of gotten the maf sensor wet? Im thinking some kind of sensor got wet and isnt working right, just got to find out which one.

i washed mine and i had small crack in the oem potting on the coil packs. did the same thing

Did you wash your engine with the car on or off? Everytime i wash my engine I keep the car running! Check your maf make sure it isn't wet like someone else mentioned and clean you IAC just in case, I know mines would sound like it was backfiring when my AIC was dirty as well as turn off on me!

Its not a good practice to wash an engine while running or hot.

I've done it for the past 2 yrs and I've had no problems yet! :confused: ...

Ive always been told water on a hot engine will possibly crack the block by cooling it too fast.

Well It hasn't happened on my car yet! :confused: ...I've heard that too, but i think thats just a myth! I always hear about the kinda problem blake is currently having with his car after washing the engine with the car off! My buddy told me to keep my car running while I wash the engine! The way I do it is I wash my engine maybe once a month! When I get to the car wash I detail my car first! Vacuum it real good, armor all, clean my wheels ect,! This usually takes me about 30-45 mins, sometimes more depending on how much clean i want it! ;) ....all while the hood is open helping it cool down a bit! After that I fire it up and wash the engine first and then proceed to wash the rest of the car! Its worked for me so far! :)

oh boy you WILL crack a block if you hit it with cold water while its hot. ive seen it done on quads, trucks, dirt bikes, and a craparo (camaro)
i say swap out your coil packs. like when you get water in the old distributors. screws everything up. just throw a friends coils on real quick and see if it solves the prob.

He has 8 coilpacks.

Compressed air
 

Best way to chase out any lingering water is with compressed air.

If you shorted out a coil pack (unlikely, in my view) you should be getting an OBD code. Seems to me that you'd code if you have a badly confused sensor, too.

Wet coil problems seem most likely, followed by water in a wire bundle, with multitude of other options falling after.

Do you have a way to check for codes?

tripleblack

Pretty sure hes already checked for codes and its not throwing any.

Wow, lots of responses.

The problem is bad. Looks like 4 coils are not firing and they are all on the same side of the engine. I think the computer is toast. Looks like a bad short-circuit.

Any ideas are greatly appreciated.

Cant you just switch a coil pack that is working with one that is not. Lucky me I only have two to worry about.

Yup. I have tried that. But, it seems as if that any coil pack on the passenger side will not fire. I don't think that it is an actual coil pack problem in so far as it is that the coil packs are not being told to fire.

If I had a complete set of coil packs, I would just swap them over to my car to see what would happen. Thing is, they are expensive ($40 each) and you can't return them. I even considered packing a friends car next to mine and swapping his over to my car. Simple enough, right? But, I am am concerned that a short on my car may be actually blowing any coil pack placed on that side of the motor.

How do I know that? Because, I originally inadvertantly mixed a few coil packs up when I was troubleshooting and chnging plugs. As a result, I made a shorted another because the car ran worse.

Then, I purposely moved one from the passenger side to the drivers side, and when I did this, it did not seem to work on the other side at all.

Best case scenario as this point:

Shot is discovered. Correcting short circuit, fixed car.

Middle case scenario:

Short has burned-up coils. Short needs to be fixed and coils replaced.

Worst-Case scenario:

Short has resulted in damaged computer modules and coils. Wire harness needs to be replaced as well as coils and computer and God knows whatever else.

Dan, here is the thing. Why the hell would a car run this poorly and not throw a code. ****, I have had codes thrown because of a silly-ass exhaust leak. I am litterally blowing gas out the tailpipes and no code.

This makes me suspect that the entire computer is shot.

If you say so..

Well, I just came back from the shop. The technician is stumped. It is obviously running like crap, but not showing any codes.

THEN, all of a sudden, they got a missfire in #5. The computer is acting goofy. He is going to try and troubleshoot #5 and see what happens.

What is really confusing him is the lack of codes.

Blake, she probably got tired of being slow and is throwing a fit! :p

PC Shorting / Sensors Malfunctioning causing a Misread? Only thing that I can think of.

Wierd Science
 

Grounding issue with computer?

Know of one case where short through harness failed to kill computer, but screwed up the ground. Computer went psycho.

Check that ground pronto. Also, may be easy fix, if its the problem.

tripleblack

Ground on the computer is good. Already checked that.

One bad COP was found...#7. The tech pulled all of them and bench tested each of them. The bad one was sporadic, but at times simply would not fire. A new one was installed. I have not picked her up yet.

Let's hope she runs.........

$20 the engine seizes.

Hope she runs blake.

Well, I got her back and she is running better than I can ever remember. In truth, I think this COP had been a problem for a long time. The car idles better and sounds better too.

The exhaust no longer pops! Word to the wise, if you have an exhaust that pops, you might be having some missfire issues.

It's a totally different car.