I've got a 99 SC1 SOHC. Here's my problem. At startup the idle goes to 2000 RPM then eases down. When starting forward at about 2MPH the idle jumps to 1700-1800 RPM and stays there until I come to a stop, at which time it comes back down. I've changed the IAC valve, TPS sensor, ECT sensor, and the MAP sensor. Still the problem persists. Any thoughts?

 

I'm going to change the throttle body gasket tomorrow as a precaution.

 

Clean the TB while you have if off.

 

Done that but not a very complete job. I'll finish it while I have the throttle body off.

 

Here's a little more info. The problem was initially intermittent and I could fix it by stopping the car, shutting the engine off, and restarting it. Is it possible that my computer has gone bad?

 

1-Maybe stop in the new member area and introduce yourself
2-Add you first name, location, yr and model to your signature
3-2 can be done in the user CP
4-Read this https://www.saturnforum.com/forum/general-tech-help-13/etcs-its-connnector-6417/

 

I'm new here. How do I get to the new member area?

 

Never mind, I just figured it out.

 

After warmup, check the idle speed in neutral or park. If it is above 1000 rpm and won't settle down lower, then check for a vacuum leak around the #1 cylinder intake manifold gasket. The outer top corner is not well supported and sometimes gets sucked in there. spray something in this area and if the idle changes, then the gasket is leaking.

 

So 99 what was the problem can you feel us in on it?