Hello, 1998 3.1 w/ high idol issue. First issue came a few months ago and I replaced the TPS and this seemed to fix it... for a bit. I will add that before the new TPS, I would see the RMP's bounce a little but nothing you could hear. staying 900/1000 RPM. Now on cold or hot starts, it will either immediately go to roughly 17k rpm or be at 1k and 20 seconds later it will jump up to 1700 or 2k and remain steady. Sometimes it will be good till you dive a min or two and I'll hear or feel the high idol when breaking. If rpm's are high, acceleration from a stop is sluggish... not down shifting when I stopped?

I don't hear any vacuum leaks, but have not done any spray yet to try and find any leaks. Should I look at replacing the Idol Air and PCV? I have newer coolant sensor level, thermostat and coolant temp sensor. Temp gauge steady just under half way.

Thanks for any help.

 

It could be the throttle position sensor. Have you cleaned the throttle body area. They get a bit gunked up like the Carburetors did. check this youitube for the TPS. Hope it helps. I did look thru the GM manual for these symptoms but I found nothing about the high idle just rough idle.

 

I have not cleaned this area. I just changed out the sensor. It certanily is goofy. If it starts fine or not, when it high idols, it goes straight to about 1700 rpm and stays there like you had set the cruise control. Thanks for the video. I'll check it out later today and with having tomorrow off, I hope to get this settled.

 

Now here is another thought if you have a salvage yard nearby, like a u pull it, you maybe able to find the same parts in a Lumina as well as the Monte. Change it out and try that too.