Help us help you. By posting the year, make, model and engine near the beginning of your help request, followed by the symptoms (no start, high idle, misfire etc.) Along with any prevalent Diagnostic Trouble Codes, aka DTCs, other forum members will be able to help you get to a solution more quickly and easily!
Hey guys, got a good one here. One my service advisors has a 2002 saturn sl1 with the 1.9. He's experiencing a super high idle in any gear and it seems to settle down in park. Car will go 30+ mph on its own with no throttle. My "master tech" colleague shotgunned an IAC and that obviously didn't fix it. IAC steps during the problem can reach 120. Car has a -20 STFT and -3 LTFT, single wire O2 reads stoic at this level. Has a single code stored for coolant temp not reaching regulated temp, which it is not. Holding 3k this temp will only hit 160 max both with laser gun and scan data. Pulse width 5ms.
Is the high idle a result of the low temp? That's a dangerous strategy if so. Hard to believe it would allow trim correction of an intentional richening.
I've encountered a number of vehicles with high idle from low coolant level or stuck open thermostat so I would say yes a low coolant temp could cause an idle issue
You said IAC counts are at 120 during the high idle? This means the PCM is commanding it and you most likely have an input issue.
Please report TPS readings KOEO and the running at idle.
It would be nice to have voltage and percentage numbers if possible.
Then look at you park/neutral switch, AC command and power steering psi inputs.
Also, what are your ECT readings compared to actual temp? Maybe you said that.
I'm not worried about the low temp, that's not causing your issue, you need a thermostat but I am worried about an inaccurate ECT, these are know for that.
