Hello folks

I have an 87 Pontiac Fiero SE with an Iron Duke engine. A couple weeks ago I had a code 45 and I was reading Ogres postings and he mentioned that I should change the map sensor. Sure enough after doing the testing, my map was bad it was the original one from 1987. Besides changing the map, I also installed a brand-new IAC & PVC valve. I cleared the codes and with the new parts installed I took the car out for a test drive for while for the computer to reset. The CEL came on twice after a half an hour drive. when I got back there was a code 35 this time I’m going to check the vacuum lines. But if anybody has any other ideas of what could cause this Code 35 after a Code 45 no longer there, that would begreat, thanks.

From Here...

quote Code 35 - Idle Speed Error The ECM will set code 35 when the engine speed is 75 RPM above or below the correct idle with closed throttle. This condition must be met for at least 45 seconds before the code is set. If idle speed is too high, check for vacuum leaks. If idle speed varies up and down, your engine might be running too lean (high air/fuel ratio). Check for low fuel pressure or water in fuel. If idle speed is too low, your engine might be running too rich (low air/fuel ration). Check for high fuel pressure or leaking/sticking injectors. Also, check all connections to the IAC and replace the IAC if necessary.

Thank you, Patrick for this information. Just an added note: When I started the Fiero today from a cold start, it started up without revving high. Even though the vacuum hoses were changed earlier this year without this problem, I plan this week on changing the vacuum hoses again.

[This message has been edited by MERATIME (edited 07-14-2025).]