My car has idled rough while stopped at stoplights for about a year or so. I've tied quite a few things to fix it such as relplacing several vacuum hoses, got a new EGR valve, new 02 sensor, and cleaned the IAC valve. However, nothing quite seemed to fix it totally. I've noticed that if I give it just a little bit more gas when I'm at the stoplights it idles perfectly fine. The other day I decided to give the set screw on the throttle body about a turn or two. (The one that stops the throttle blade from moving all the way back.)

Will turning that screw hurt anything? I think that it was adjusted previously because I thought I read somewher that there should be a cover over it if it has never been messed with. When classes let out for Cristmas break I plan on adjusting the TPS. (I don't have my Volt meter with me at college) When adjusting the TPS, does it matter what position that screw that I turned is in?

 

If you go to the home page of thirdgen.org youll find tech articles on all this.

 

i had adjusted my stop screw for the throttle blade a while ago, and didn't notice any problems with it...And i highly doubt that it would make a difference to the TPS since the TPS will simply recognize the position of the TB Butterfly. What RPM's does ur car idle at right now? it's possible that the idle has been adjusted sometime in the past and is set to low, so the car is simply trying to "stay alive".

 

Thanks for the reply br()bert. I read the TPS part of that article a few times, but I must have missed the part about that screw in the iac section.

85f-bird, I'm not sure what my RPM's are at. Unlike my 84', my 85 doesn't have a tach guage.

 

Your welcome

 

I bought a gasket kit for under $10 that has every gasket for the throttle body. If you have any leaks around the throttle body that would help them out. I had a problem such as yours but I found it improved when I replaced a frayed wire to a fuel injector harness.

I would think drilling out the cover over the idle set screw and moving the screw forward is just masking the problem. If it ran from the factory set that way it should run that way when the problem is corrected. Checking the TPS is a good idea and checking the IAC ports for blockage is also an idea.