I have a 1994 C4 LT1 P Vin....It sat at the chevy dealer for 6 months while they worked on it...it idles at 1200 - 2000 rpm...they put in a new tps, tps modulator, new IAC, new ecm...it currently has the same probs..the asr and check engine light are both on...the only code it has is for a tps...have put 3 new ones in...the only way to idle right is to wallow out the non adjustable tps holes and "tweak it down" i know this isnt the right way...please help any ideas?

 

Any mods? can you make it idle down by manually pushing on the throttle lever? unhook the cable, any better? if no help I would remove the throttle body and disassemble and clean. If not any of these I would look for vacuum leaks and check the coolant temp sensor. GOOD LUCK!

 

High idle is caused many times by vacuum leaks. Could even be an intake leak.

I would also get it away from those clowns and find someone who can work on a C4. Check with the local vette club in your area if there are any.

This place is throwing parts at your car and not properly diagnosing it.

 

Thanks for the advice...i will check for vacuum leaks and try without the throttle cable....seems like the "pros at chevy" and i use the term pros with great sarcasm as they had it from aug 09 to jan of 10 and still didnt fix it...keep telling me that it is electrical in nature...also that the average guy cant work on these as the iac/tps/ecm all require a tech 1 or equiv. to program all the sensors and such...that leads to another question...the car has the 16 pin OBDII connection under the dash yet is still on the OBDI system as the ecm/pcm original to the car has a removable prom? is this correct? i have been told that 94 was the conversion year from I to II and some had OBDII connections although the software was still OBD I ??...thanks for everyones help...i think i have finally succeded in shelling out more money to mechanics than the cars actual value!....However I LOVE my Vette....although the wife is kinda ticked it came back still broken

 

Ps...No mods all stock..

 

kenny

http://forums.corvetteforum.com/search.php

go to the search engine on the forum in the key words type high idle and then go down to bottom right and highlight the C4 section (this tells the search engine where to search)

and start reading threads. I and many others have spent hours reading these things and sometimes the answer is found there. There are many who don't come back and tell us what fixed their problem so every thread doesn't have the answer, you just have to keep hunting and pecking until you see something that was a cure with your symptoms. that doesn't always fix your particular situation but it gives you more knowledge than the mechs at the dealership seem to have.

Also remember to come back and start another thread that, or add to this one, and tell us what the fix was. I was looking at several old threads today that discussed your problem and there were several different cures. So best of luck and don't be afraid to come back and ask more questions. I am not an expert but there are many here who are and you just have to catch them on line.

I have an issue I am working on myself but I am reluctant to send it to the dealer to be diagnosed by people who probably have little to no experience with these things.

And buy yourself an FSM if you don't already have one. And take your wife to dinner and tell her we will get this thing fixed.

when you type the words in the search engine and select the C4 target area and hit enter it will pull up something like this

http://forums.corvetteforum.com/sear...rchid=14558600

see, you are on the front row!

One more thought. I read a thread today that a member was trying to tell the OP what to fix and he didn't listen. About 1k later he did and kablam! problem fixed. So listen to these guys and be patient on catching them on line.

 

Your 94 should be an OBDI with the 16 pin DLC, look under the hood at the Emissions label.

 

I'm thinking 96 was the actual required conversion but some cars started before that, I may be wrong.