2G high idle when hot

[billko]

Hi, everyone:

I have a problem that just suddenly popped up. After the car has been sitting for a few minutes, when I start the car, the idle is really high. Tapping the gas pedal doesn't really do anything. After it has been running for a while, it seems to be okay.

I've seen a few threads that suggest this could be a bad water temp sensor. Your opinions, please?

Thanks!

[edit]
I meant to say after driving it around, getting it up to temp, and shutting it down, then starting it back up after a few minutes.
[/edit]

 

[pacn91]

vacuum leak?

 

[billko]

Ugh sorry, you probably posted before I edited.

 

[DSM1G90]

ISC motor could be acting up in finding that sweet spot. Could be getting tired and needs reset or replacement is approaching.

 

[billko]

Sorry, I haven't abandoned the thread. I was trying to refine what it was doing. I'd like to re-explain. When I first turn it on when cold, it is fine. If I let it warm up to operating temp and then turn it off, let it sit a few minutes, then turn it back on, then the problem happens until it has been running for a while (unfortunately I haven't been able to determine just what "a while" is yet.) I've read this article. What do you think of it?

Thanks!

 

[dsmreck]

what is tps volts before start up? I have seen a strange issue with the throttle cable tightening after warm up. Also isc and fiav or boost leaks are very common issues

 

[billko]

The last car I seriously worked on had a carburetor. (At least it wasn't new.) I do know how to use a DMM, so I'll poke around the forums and see how to check these things.

Thank you for the guidance!

 

[billko]

Hey, I finally got some time to actually dig a little into the issue. Additional info here is that it is not surging - it is steady, holding anywhere between 1k and 2k RPM. While it was running high, I was able to push on the throttle linkage to get it to drop to normal. I then used the linkage to rev the engine to the same range where it sticks, and it does. But only when hot. Also, when revving, the exhaust did not seem to be rich or anything. (Stinging-eye measurement method.) I read up above that, unbelievably, it could be a throttle cable issue (sticks when warm). Does that make sense? I would like to avoid taking stuff apart because this is my commute car and I can't afford an "oops, I didn't do this right and now I have to wait for parts" kind of mistake.

I'm going to check the cable at any rate because it's an easy thing to do.

Again, any help or advice is appreciated, and I am not afraid to do the legwork and find out how to do whatever it is you are suggesting. (For instance, I saw a few you-tube videos on how to check the ISC.)

 

[Fullthrottle7]

Yes, the throttle cable sticking when warm is a real issue. Didnt believe it at first when I had this problem come up and chased several other things until I saw the throttle cable issue in several threads. Loosen the two 10mm bolts holding it in place and slide it very slightly to the left and clamp bac down. You'll be all set from the sound of your troubleshooting!

 

[billko]

Sorry about the intermittent posting, but like I said, this is my commute car and I don't get to work on it as much as I need to. Anyway, I tried the adjustment and it seemed to work - I only tried it out once, so I only have one data point. But I'm hopeful!

Thanks for all your help so far.