Hi, my throttle on my t5 lb9 stays high around 1500 when coming to a stop in neutral until I blip the throttle. When driving at low speeds it feels like it has cruise while in gear intermittantly. If I blip the throttle it will then go to normal idle. Never seems to do this at more than 2000 rpms tho.

I cleaned the iac and passages when I rebuilt the engine and it did this before the rebuild too sometimes.

I also set the tps, but when following the haynes manual it says to disconnect the Iac when setting idle speed. My car would not run at all without Iac plugged in.

Seems to idle very well except when its warming up idle goes up and down for a few minutes like its trying to find the lowest idle point.

Anyone see this before? I dont see any binding in cables or throttle body.

 

Idle control for manuals and automatics isn't the same.
TPIs don't come with standard transmissions.
There is no TPI ECM EPROM code for a manual transmission, you'll need someone to help you reprogram a TPI EPROM for a manual, or reprogram a manual EPROM for a TPI. I'm sure there's lot who have done the conversion, and it just may be a couple of simple parameter changes.

 

the only tpi that came with the 5 speed is the lb9. thats what I have and the engine and transmission in it came with the car from the factory. l98s were all automatics from what I understand.

I bought the car from original owner with receipts. maf and ecu were replaced before for idle issues, so maybe it is a programming issue.

I could understand the idle staying around 1000 while in neutral coasting to a stop then dropping down to 600-700, but 1500-1800 rpms steady even after car is stopped untill throttle is blipped seems to be a problem.

I think Im gunna try a tps even tho I have my doubts.

 

My auto has similar issues, but the throttle staying at 1500 is a sticky throttle body for me. Same exact thing, sticks at 12-1500 untill I blip the throttle. I took it apart, cleaned it, replaced all the gaskets, and oiled up the moving parts really good. That stopped the throttle sticking for around a week, now it still does it. I think your throttle body is wore out. Vacuum leaks can also develop around the shaft, so I was wondering if that could be causing the whole "hunting" for the correct rpm thing.

 

I had the same problem with my LB9 T5 (which does exist by the way). I went through and replaced all the vacuum lines even though I didn't think I had any leaks. Apparently I did have a leak because the problem went away after that. It does idle around 1000 while coasting but drops to about 700 when I come to a complete stop like you were saying.

Check all your vacuum lines carefully, especially the ones under the plenum. Those were very brittle on mine. Also make sure your throttle plates and linkage are clean and not sticking or binding.

I would agree with looking into the possibility of a bad tps too.

 

I stand corrected.