2K rpm idle

[BlueBaron]

87 T1 Auto
Code says TPS circuit. I tried another sensor. It'll start out idling fine. But after a few stops at intersections, the car decides 2000rpm is a better idle speed.
Shut it down and restart, it'll go to 2K, then settle down to 700 or so (normal).
But then a little driving and it does the same thing.

Ideas?
I can go looking for my old Logic module if it's worth trying that swap out.

[cordes]

If the old TI cars have even a small vac leak they can race like that from what I've read. Check to make sure there are no leaks and everything is sealed up near the TB. If that checks out I would then look at the wiring to the TPS since you are getting the code.

[BlueBaron]

I tried pulling the plug on the TPS while it's running. Worst it did was go to 1500rpm (or so) Not 2000. The owner doesn't think the check engine light came on when it was idling at 2000rpm before. TPS problem does activate that light.

If it does idle high, it goes back to normal on the next restart. So I doubt vac leak.

I'm gonna see if I can swap the AIS next. I think it's making a squeak sound now and then. Can the AIS actually reach 2000rpm if the throttle is closed?

[cordes]

If the AIS is stuck all the way open it could cause a pretty high idle in my experience.

[mcsvt]

Speedo working? I had a high idle when coming to a stop when my sds was bad.

[Murphy]

AIS all the way open should be about 2000rpm.

[bakes]

You have access to a scan tool. if so look at the steps if they are higher then say 30 then look at the other sensors like coolant temp or SDS . If the steps 0- 7 then look for a Vac leak or sticking TB or Ais

[zshadow]

AIS all the way open should be about 2000rpm.

isnt there a way of tricking the computer to force the AIS 100% open, then to reconnect it and it should run correctly?

i may be wrong...

[Murphy]

start the car, pull the brake booster line, unhook the AIS plug, hook up the brake booster. that will make it CLOSED and idle at its lowest setting

[BlueBaron]

I haven't had a chance to look into the AIS any more yet. But can the AIS go wacky without the computer noticing? I'm referring to no AIS code coming up.

And no, I don't have a scan tool handy. Just the onboard check.

[cordes]

I haven't had a chance to look into the AIS any more yet. But can the AIS go wacky without the computer noticing? I'm referring to no AIS code coming up.

And no, I don't have a scan tool handy. Just the onboard check.

I've had them get gunky and require a thorough duching with carb cleaner to function right again. No codes.