tried to search under itec for answers but didn't see much. Anyways, I just picked up an '89 RS and seem to be having problems with a sticky shaft in the throttle body. When warm, and backing off accelerator, the engine will "hunt" for idle, revving between 1000-2000. Also when this is happening the accelerator is ultra sensitive in the lower rpm's. 1st thought was throttle position sensor: replaced to no avail. 2nd was O2 sensor: replaced and no results. MAF sensor? maybe (it "clicks" when coming off idle). Also, no codes are being shown (except 12,12,12...) So I finally got the symptoms to occur in the driveway, and it appears that the shaft with the "bent tang" (upper) hangs up ever so slightly and won't always return fully. Anybody else ever see this? Many thanks, Tom.

well, I added an additional return spring just to check my theory, and the Trooper is running great with no more "hunting" or super sensitive throttle. Looking at throttle bodies in the junk yard, it appears the upper "tang" (L shaped part on upper shaft) may be bent out of adjustment. I may try to readjust, or just run as is. Tom. (just posting info for referance, 'case anybody else is having the same problems)

When you replaced the TPS did you calibrate it? I messed with mine and ended up with the engine hunting until I calibrated it. Vacuum leaks can cause problems too.

yea, I figured vacuum leaks would be a major PIA with all that hose (in process of replacement now). and no, I didn't recal. TPS. I noticed the mounting holes were slotted and tried to line up like original. But the rigged up return spring did solve the driveability issues as well as the idle "hunting". It looks like the "L" shaped tang on the upper throttle shaft (front side) is twisted out of spec (from all the junkyard models I looked at). I don't know it's purpose, but when I finish with the overdrive problem in my Dodge, I'll "recalibrate" that tang.