My 88' Z31 high revs to about 3k-3.5k ish rpms when I start it up and drive. (That's driving normal speeds around 55 MPH) I've read on Yahoo Answers that the TPS (Throttle Position Sensor), might be sticking? Any ideas? I start my car up and let it warm up for 10-15 mins everyday in the cold weather before I go off and drive it. I figured that if it high revs, it's bad and hard on my engine. Any solutions?

 

warming up for 10 minutes wastes a lot of gas. A minute is sufficient to get oil moving thru the engine. get the fsm from xenon website. read up on what gizmos affect the idle and go from there. tps not your problem.

 

Ok well I was told by my friend that has multiple Z cars that they're known to high rev when driving before they're completely normal. I guess that's just the way they're built?

 

3K rpms is way too high for any car just idling and warming up. Does it come down after to drive it? Is this the same car you posted about overheating? High idle is usually caused by a vacuum leak somewhere. Did this just start happening out of the blue or had you done a repair or changed something and then it happened?

 

After the car warms up, the idle goes down to normal. But it high revs to 4k rpm's when driving on the roads when the engine is cold. But when it warms up to operating temps, it goes to normal. Yes this is the car that has overheated once.

 

Is this Z an automatic or manual? I had an 87 300zx n/a 5-speed and never had this type of issue. Definately check all of the vacuum lines and throttle cable for adjustment.