engine idle

I have not been able to correct the idle on my '82 crossfire corvette. I have replaced,the plugs,wires,iac motor,fuel filter, and temp sensor. It still revs high then low or will die.  Any suggestions on what else could be wrong? I'm thinking of replacing the fuel pump next. Thanks, Sal Forgot, also replaced map sensor.  

vacuum leaks...  

pinch off the power brake booster hose  for a few seconds.. or plug it...  you don't need it for testing.. and they can leak enough to do exactly what you are describing...

the lower intake manifold gasket could be leaking...    the upper could be leaking...  the throttle body base gaskets could be leaking.     the EGR valve could be leaking...  

it just really sounds like a vacuum leak...

how is the ignition system.????   have you taken the cap off and inspected inside for carbon build up... have you inspected the COIL in the cap????   look for circular powder marks.. that would show high voltage leakage to ground..  these coils go bad a LOT>..  and they are cheep.. at least at autozone..



i am thinking that your corvette has an ALDL connector under the dash board..


you might need a scan tool....

search craigslist... in your area...    search for the terms..   MT2500   or  monitor 2000,   monitor 4000,  tech 1 or tech 2..


there are scan tools still available that will allow you to look at the sensor data on these systems...

probably one of the equus OBD1 and OBD2 models...    available at sears or oreillys.. AKA checker. shucks, kragen..

i don't know how many of these will be displayed on that early system... but this is the information you are looking for...

i would print several of these charts.. write the info down line by line from your scan tool so you can sit and compare it.. and or post the data...    you will have to copy and paste the link below into a new window to open it.. or copy the entire text and paste it into an email to your self.. the link will then be clickable...

http://repairguide.autozone.com/znetrgs/repair_guide_content/en_us/images/0900c152/80/06/7e/6a/large/0900c15280067e6a.gif



there are also several articles on the crossfire here in the magazines...


one more thing...   this is just a TBI fuel injection system...  just like was used on other gm cars and trucks up through 92... millions of them... its just in a slightly different configuration than most people are used to looking at...



i found this from one of my old posts...


http://www.corvettefever.com/techarticles/4688_chevrolet_corvette_efi_system_tuning/index.html

this one goes into making more power out of them.. but has great pictures and info... to make you more familiar with whats going on under the air cleaner..

http://www.corvettefever.com/howto/51218/index.html


these 2 might be worth 10 bucks...

http://carburetor-manual.com/corvette-crossfire-fuel-injection-service-manual-p-311.html
http://carburetor-manual.com/1982-1984-corvette-crossfire-injection-electronics-manual-p-1423.html

maybe 3

http://carburetor-manual.com/1982-1984-corvette-crossfire-throttle-body-injection-manual-p-1424.html