I just bought a '85 gsl-se, with 100K on the motor. It has been babied from birth by my mother in law.

Anyway, when I start it up in the mornings, sometimes the idle runs up to 3000 rpm, very fast. I will stay there unless I put a little load on the engine to drop it, and then it will run about 2000, until it warms up.

This morning, though, when I got home from work(30 minute drive), it did something very strange. When I pulled in the driveway and took it out of gear, it started reving itself, from 1000 to 3000. Up and down, up and down. I shut it off, then restarted it. It then acted cold, although it was warmed up.

What controls the idle speed, and why would it do this?

 

sounds like you have a faulty throttle positioning sensor, or yours is badly out of adjustment

 

This is unfortuantely a very common problem on the se's, get a haynes repair manual or
do a search thru the threads, it is a multiple step process of checking the system and takes
awhile to verify everything from the tps adjustment to all electrical connections to proper adjustment on the t/b and could lead alll the way up to a pin test at the ecu. Yes it is the
biggest nightmare on the se's. Remember what doesn't kill you, makes you stronger. Or in this case gives you a major headache and challenge. LOL. rx7doctor

 

I'd also say start with the TPS.
Here, this should help you with any idle issues... http://www.nellump.net/peri/epi/firs...gslseIdle.html

Also, since it's been 'babied' for 20 years... I'd recommend some kind of a powerfoam treatment on the engine.... then make sure you always rev it up high every once in a while.
Oh yeah, and show us some pictures!

 

Yea, I found the links to the idle problem, so I will get it fixed. I know alot about conventional fuel injection, so I had a pretty good idea what could be causing it, I just haven't had time to learn my engine. I am getting the repair manual from my father in law this month.

As for powerfoaming it, I really don't think that I need to. I have been driving it like I stole it since I bought it a couple of months ago. Keeping the revs up, to get the carbon out. It is running pretty clean, keeping a close eye on the ol right now.

This car has never seen a winter, but has been run every week while in winter storage.

The only flaws on the car is the paint('cause it is old, faded and orange peeled in a couple of spots); and the mat below the hatchback is pretty faded. Everything else is perfect. The seats and interior are very new looking, no stains, I even still have the cover for the sunroof when I take it out.

I will post some pics in a couple of days, When I get a chance!

Thanks for the interest!
Ken Johnson