The L98 idles fine at 700-800 rpm when cold and in park, or neutral..... but after running the car around town, or after 30-60 mins (depending on how hard the car is driven); the car in park or neutral will idle anywhere from 1400-1800 rpms. The engine is stock and the timing is set at 10 degs. It used to just idle around 1200 - 1500 rpms, but it has now recently jumped up. What do you guys think might be wrong, or what do i need to check out?

If you need anymore info, let me know what else information might be helpful. Thanks in advance!:hail:

 

I would start with removing the throttle body, remove the IAC, and clean all the carbon off the pintle and orifice. Set minimum air and TPS and see how it idles after that. There should be a tech article on all of this in the tech section.

 

I have cleaned out the carbon deposits on the TB by spraying the TB with a TB Cleaner that is O2 sensitive while the car was running. I ran the car for about 30 mins and did some wot's.

I know how to set the minimum air, but i do not know how to set or read the TPS. I read that the TPS is directly underneath the IAC i believe.

I pulled 5 spark plugs, 1,3,5,7 and 2. The easier ones, and did a quick compression test. All read 150 p.s.i. or so; except for #3. I didn't get to pull off the other 3 because i did this at school and we only have a certain time frame to work with. The thermostat and the waterpump are both working. The thermostat is a 180 deg. The car will overheat if i am in traffic too long, or from stoplight to stoplight. The fans are turned on by a toggle switch manually, and the car wont overheat on the freeway.

I am guessing that my car is getting hot because of the rpms that it is at. In drive, the car rpms from 1000 - 1200, but when i stop somewhere and put my car in either neutral or park to turn it off; rpms just shoot upto 1500 - 1800 rpms.

Thanks for your reply RBud350tpi. If you have any more helpful info or ideas, please let me know. It is annoying and embarassing for me to turn my car off at 1800 rpms, and probably not any healthy either....

 

The only way you are going to get the carbon and dirt build up off of the IAC is to physically remove it and clean it. The TPS is located on the passenger side of the TB. Its voltage should be set at .54. I used to have the same problem though not as high as you and cleaning the IAC took care of it.

 

The IAC is probably the problem, but look at the side of your throttle bracket (when the car is idling high) and see if the throttle lever is touching the adjustment screw....mine doesn't like to return all the way back sometimes. Does the idle go down when you "blip" the throttle?

 

cool, tomorrow i work all day, but i have saturday and sunday off.... guess what i'll be doing!

I'll keep you posted if this helped out or not.

 

hey ir0cz!
yeah, that was one of the first things i checked out.... and its not sticking... thanks though!
:hail: