I've been trying to fix a high idle problem for quite a while and I can't seem to figure it out. It usually idles from 1.2k to 2k rpm when it's cold and it idles this high even after it has warmed up. The longer I drive it (more than 20 min), the lower it idles. Most of the time it will idle at 1k rpm when it's warm. Every once in a while it will drop down to 800 rpm. Some times when I push in the clutch, it will rev to 2k rpm, drop to 1.5k rpm, rev back to 2k rpm, and repeat.

I've thoroughly cleaned the iacv, bled the cooling system, and checked for IM leaks. IIRC, the coolant temp sensor is fairly new. I don't think that the tps is bad because it seems to be working just fine with my vafc and my nitrous controller. When I pinch the pcv hose that's located on the back of the IM, the idle drops about 300 rpm. Is this normal?? Does anybody have any other suggestion as to why my idle is so high?

 

Other than TPS and PCV valve replacement, have you checked your throttle/cruise control cables to make sure they're tensioned correctly? Something that can easily be overlooked.

 

+1 on TPS...My car will sometimes idle 1500rpms even after its warmed..I wiggle the TPS and it settles back down. My harness for the TPS is broke, and let to wire corrosion, no matter how much cleaner i spray in there and contact grease I put on. I will have them problem until I splice in a non corroded harness or just solder the wires directly, which I want to avoid.

Not sure what would cause it to jump from 1.5k-2k. Im either thinking your TPS is bad or the connection to it is bad.

I think if idle drops when you pinch that hose, you have an intake leak? or maybe that means its normal, I forget, maybe someone can chime in on that.

 

I think it might be the tps. I unplugged it and plugged it back in a couple of times and the idle has been staying around 800 rpm.

I definitely know not to make the CC/throttle cables too tight. I learned the VERY hard way. When I did my vtc's and chain tensioners on my other engine, I installed the CC cable barely too tight. When I fired up the engine, it revved to 4k, and I immediately shut it off because I thought something was wrong. I fixed the CC cable, started it again and it was running on 3-5 cylinders. Then, I realized that the timing chain had skipped a tooth.

 

I think you might have a bad connection @ the tps, not a bad tps unit. If the sensor is bad, it wouldn't make any difference if you unplugged/plugged back in, it would still be malfunctioning. smash the female connectors down a little on the harness, and make sure there is no corrosion present.

I also suggest you check all the other sensor connections with the square type connectors for looseness/ corrosion..

 

ya definately sounds like its the connector piece possibly being corroded or just making bad contact giving you the intermitent problem. You can bend the teeth inside the connector, like greeny mentioned, so when you plug it onto the TPS it should fit more snug.

PS. Did you rebuild your VTC yourself? Im trying to find the kit to rebuild the VTC, I think its a new spring or something that you put inside the assembly. Was it running on 3-5 cyls because it skipped a tooth? Sorry for off topic

 

at least it is a VE with this issue. I say that because the VE uses a more "modern" consult system than the VG did. If you can find a shop with an MT2500 snapon scanner (or newer version) with the NISS-2 connector than can read all the inputs of the ECU and that may tell you what sensor isn't supplying the correct data to the ECU.