Just got the '92 RS back from the shop with it's new motor.It runs great, but there's one little problem.It idles at about 2 grand in neutral or park, and about 1500 when engaged in drive with my foot on the brake.All I have to do is lift off the brake pedal and I can do between 15 and 20 mph easily.If this were a carb vehicle I would have easily fixed this.However, I don't know monkey poop about TBI and I don't want to eff anything up.All new hoses and hardware was used in the install.I know I could simply take it back to the shop,but it's a ways down the road from me and it's a PITA for me to get a ride home,.Also I want to take it out for an extended cruise, cause I've been without it since Xmas.Is there anything I can check or adjust fairly easily?Thank you in advance for your help!

 

possible bad idle air control motor. big vacuum leak. improperly adjusted timing. does it change as its get warmer? could be a coolant temp sensor problem also.

 

Check your IAC valcume i'm a big noobie to cars but mine was doing the same thing. The hose wasn't connected as the end result. Popped it on and now idles around 800

 

I wouldn't think it would be the timing because it fires right up and is smooth throughout tie RPM range.Temp is not a factor here;I can take it for a 20 mile drive and it still does it....

 

Check your gasket seals, egr, etc make sure all that is in the clear of loose bolts etc.

 

I have a very similar problem with my 92 RS, I changed my CTS (coolant temp sensor) and that fixed the problem immediately. Its cheap and easy to do so I would personally start there.

-Darren

 

you can also use an ohmmeter to check if your CTS is good or bad.
measure cold and warm and compare your readings with this:
https://www.thirdgen.org/forums/atta...mp-tempse1.gif

otherwise the iac might be something to look into. if you have a vac leak you can localize it by doing the starter spray trick.
hth ownor

 

I may want to add another detail here guys, it FAILED EMISSIONS!!Hydrocarbons were too high; the other levels were okay.Hope this narrows it down some.

 

high hydrocarbon's means unburnt fuel. I would think with a vacuum leak your NOx would be a little high due tot he car running lean and causing your combustion chambers to run hotter. Now if your car was running rich, like it just might with a bad coolant temp sensor then your hydrocarbons could also be high. your timing is computer adjusted, so thereofre if it were incorrect the car might drive okay still but be off at an idle.

 

I have decided under further review,WTF,I'm going to do the right thing and take it back to the technician.After all, I paid good money for this motor and there's no use in doing the 'replace and hope' thing.I'll take it to the man and have it done right.I'll let you guys know what the culprit was, and whoever guessed closest will win a big empty box with a hole in it!Update: finally got it back from the shop and he said it was part of the cruise control circuit 'hanging up'.I guess that big empty box with a hole in it will have to go back in the hopper 'til next time....LOL