my 87 5.0 bird has a random high idle issue, there are no codes, I've cleaned the IAC then swapped it for another one I had on had. She doesn't do it all the and there seems to be no rhyme or reason as a matter of fact it wont do it for a couple of days then all of a sudden it will start up again, other than that she runs fine its just annoying sitting at a light and all of a sudden the idle jumps up...any thoughts
What is the idle speed fluctuation?? And did you do a MIN IDLE SETTING. What is your TPS voltage?? Should be around .50-.60 Volts MAX. Never exceed .60 Volts on a TPS ADJUSTMENT shoot for .55 Volts and do you have a IAC restrict-or i posted many times before for this issue. Also did you do my IAC mods and completely disassemble it and polish the seat and valve. those IAC valves are finicky. If when removed you can blow air through it it is NG. Use my mods and your idle issues will be over. That is of course unless you have a big cam and that is another story. Or other issues like a vacuum leak ETC. have a great day guys
The tps voltage doesn't. Matter as long as its between .6 and 1.27 volts. The computer knows no difference.
Give your salt and pepper shakers (injection harness to main EEC harness connectors behind the intake) a look. I had all kinds of random issues with mine only to find out that the connections had become expanded over time and I was getting intermittent contact which resulted in weird codes and mystery issues with no codes.
Darren
that was going to be my recomendation. Ill see if I can find a link.
My 88 used to do this occasionally took. Sometimes, if my foot wasnt on the brake hard enough the car would lunch forward. I wen through and cleaned everything like you mentioned, cleaned every contact on the salt and pepper shakers like other have mentioned, and never definitively found the problem. I had a code in my computer, something like a pin 30 disconnected or something, and it was the last thing I ws going to try. Have you run codes and come back with 'All Clear'?
I ended up trading the car in fora Genesis Coupe in March of 2011. (Worst mistake ever).