TPS Issues
 

Just the other day I had my mechanic check the TPS (and clean the throttle while he was there). As I had thought, an adjustment was necessary.

HOWEVER!

The TPS was so far out of range that an adjustment would have been pointless. As I understand it, the TPS should be at 10 - 12 KOhms when closed, and subsequently should be at 3 - 5 KOhms when open.

My mechanic reported that my TPS ranked in at 3.6 KOhms open (fine), and at 0.5 KOhms closed (waaay not cool). Is this right? At that point, it seems to me that my car would have some serious performance issues when approaching WOT, but everything seems to be pretty satisfactory. On cold mornings, there is an idle fluctuation for approximately 5 seconds, and a very slight idle pulsing on most days. He suggests TPS replacement. Anyone share his opinion?

I also pulled a code 37 from the ECU (number 2 O2 sensor inoperative). The idiot light only comes on during those cold mornings, not too long after the idle fluctuations. I realize that the O2 sensor issue may sound unrelated, but both the sensor and the TPS help control a/f mixture.

After the throttle cleaning, the idle pulsing seems to happen less often, and I have yet to see the return of code 37. Performance seems slightly smoother as well, but that could be nothing more than placebo.

Since my car runs *well* and I haven't seen the idiot light come back on, should I be concerned about about any consequences from my faulty TPS in the near future? $0.02, anyone?

the TPS has three wires as it's basically a rheostat. seems likley he measured across the wrong wires to have the resistance go in the wrong direction. That doesn't mean the TPS isn't bad tho - I can't say as to that. If my memeory hasn't totally failed there should be an old post by Beav in which he describes the need for something like a storage O-scope to check the TPS. Search is your friend in this case.

I definitely did some searching, and a lot of reading on old posts. The only problem is that I don't have the means to check it myself (thus the reason I brought it to my mechanic!). I just thought I'd ask some of the know-alls around here ;)

Ohms don't cut it...
 

Almost every TPS out there adjusts to 0.5v at closed throttle, 4.5-5.0v @ WOT (wide open throttle.) Check it with a voltmeter and the ignition turned 'on'.

There was an error in the original Factory Service Manual.
They did mix up the open and closed values.

Don't bother measure resistance - measure the voltage on the middle pin of TPS. (I used a thin wire strand I run through the connector). Beav is as always correct - you should see 0.5 v at closed and > 4 v at fully open. If you have to adjust TPS - aim for 0.5v at fully closed throttle.

I believe the resistance your mechanic quoted (3.6k - 0.5k) is perfectly normal.