95 Max gle, 105k orig miles.


This problem happens one out of 10 startups. When engine is started rpm's will vary from 650 to 1200 and after about a minute will settle down at 650. If I immediately shut off engine and restart this will not reoccur, it will idle normally. This can happen with engine warm, but most of the time it is when I first start up (garaged) in the morning. I do not see any engine codes, there are no stored codes. Over the last 2 years I have changed MAF, TPS, all coils, iridium plugs, fuel filter. I have cleaned IACV, TB, smog tube. I have seafoamed engine twice. This has been going on for several years. Could this be a sensor?

 

Likely still the IACV.

When you cleaned it, did you use the write up on here that shows you full disassembly?

Most don't know what all is involved just by looking at the part and pieces get missed during cleaning.

 

Yes, I took it apart per post from andrei3333 from 2007. It was pretty thorough. I also recently ran two applications of Techron total fuel system clean, that sure made throttle response better.

 

It's the tps sensor that's adjusted wrong. If the Tps setting are not accurate it will causes the rpms to go up and down because the signal is tactic due to wrong adjustments. It has happened to me before and I gave up on adjusting the Tps and just bought a used original throttle body with factory Tps settings and has worked and idled like a new car. Honestly the only people that know how to properly adjust the Tps are the dealer.

 

I replaced the TPS about six months ago because it was giving me a CE code. I went through an idle adjustment that I found here on one of the forums. Seemed to idle fine and steady after replacement with no further codes. I had this in originally to a Nissan dealer to fix, and they could not find the problem because it is so intermittent.

 

Did you adjust the tps sensor yourself or did you have someone do it? Either way it sounds like the adjustment is off.

 

I did it. I guess I don't understand that if is a TPS adjustment, then why doesn't the idle vary every time I start the car. Also, when I am in gear (auto), the idle never varies. Sometimes, I can go two weeks without this happening.

 

because it's an older car and stuff wears out. my car has an egr code and chuggs away like a locomotive when i start her and settles down when after she warms up. welcome to the wonderful world of old cars