PITA Idle Issue - Procedure Question

[js139]

Hey Everyone,

After about 2 hours of reading and researching, I think I finally found the issue my car is having. Currently, my car seems to run great until it warms up, but then it idles really rough. The idle goes down and the whole car sits and shakes. It doesn't matter if it is in park or at a stop light. When moving, the car seems to run fine, but just a hair sluggish.

Anyways, after researching, I found a post that fit my symptoms exactly. Their issue was with the butterflies on the intake. They were chipped or warped and a little gummed up. They sprayed brake fluid in them to clean up the gunk and said the car ran great after that. My question is do I have to pull them to perform this procedure or is there an easier way? It makes sense to me if I was going to pull them to just replace them. However, I thought I would put this up here and get someone else's opinion on it.

Any ideas about how they went about performing this procedure?

thanks in advance!

 

[jayro]

To get to the butterfly's you would need to remove the intake and disassemble it. Not a difficult procedure, but it may take a little time.

But before you do that, I would check some other things. Did you try and pull codes to see if there are any stored? Have you done the idle reset procedure? Is yours an MTX or ATX? If its an MTX you can check for proper butterfly operation by having the car in nutral with the hood popped. Rev it by hand with the throttle body to see if they open and close correctly. If its an ATX I'm not sure how high you can rev it in park. Stuck butterflys can effect performance, but I dont think they would effect idle at all. Have you tried cleaning the MAF? How old are your O2's? The computer switches the way it handles fuel etc when the engine reaches operating temp vs cold. Pull your codes and report back. Good Luck.

 

[js139]

It has been a while since I have done a big service with the car. It is an ATX. The O2s have probably 40k on them. I have not done any cleaning of the MAF, which is something I have been intending to do. I was planning on doing this at the same time. I have not checked the codes yet, but will be doing so shortly.

I was intending to do this, but I figured I would start here with some research so I can direct my efforts. Normally, I would have started with the stuff you suggest, but I have been super busy with work the last 2 months (i'm a CPA and it is tax season), so I have not really had much available time. In the post I found that fit my symptoms exactly, the guy with the issue did all of these fixes which didn't fix his problem. He replaced tons of sensors, TPS, CAM, etc. and nothing fixed it. He took it to a shop (owned by another SHOforum member) and this was the fix they did. I didn't want to recreate the wheel unless I needed to.

I will pull the codes tonight and post the code errors I am getting.

 

[msteiny]

ECT, Engine coolant temp sensor.

Typical symptoms of failure can include poor idle quality, rough running, loss of performance and poor fuel mileage, but of course these can also be caused by other issues. Usually a trouble code will be set during failure, causing the "check engine" light to come on.
If you're troubleshooting a driveability issue, always start by checking and diagnosing the trouble codes.
"The engine coolant temperature sensor (ECT) detects the temperature of engine coolant and provides this information to the PCM (powertrain control module- computer). The ECT signal is used to modify ignition timing, EGR flow, and air-to-fuel ratio as a function of engine coolant temperature."

I took this from the RCM website, I had the same problem with my 93 ATX. Hope this helps.

 

[itwonder]

Does it have EGR? EGR stuck open at idle can make for rough idle. Let us know how it turns out.

 

[js139]

Thanks for that info. You know my temp guage acts really eratic at times. Some times it seems to read fine, and then others reads hot, but the fan isn't coming on (but does work). I will replace that if these two things can be linked. Thanks so much for the info. I am going to pull the codes tonight and get back to everyone.

 

[rubydist]

a bad ccrm can cause the fans not to come on when they should to keep the coolant temp in the desired range.

 

[msteiny]

Thanks for that info. You know my temp guage acts really eratic at times. Some times it seems to read fine, and then others reads hot, but the fan isn't coming on (but does work). I will replace that if these two things can be linked. Thanks so much for the info. I am going to pull the codes tonight and get back to everyone.

The temp sensor I am referring to is the one that talks to the computer. It has no effect on the gauge, and is located under the throttle body by the thermostats housing. The sensor for the gauge on the dash is located more towards and down behind the coil pack. I could go on but lets see those codes.