legendaryhero7

Sorry for the double posting, it seems as though this board might have been more suitable for my question.

I've been having an issue with my TPS going out every 2 or so months. By going out, I mean that it will start to idle poorly, sputter if I'm cruising and lightly pushing on the gas, it'll die sometimes when I come to a stop, and the idle with go up and down when it first starts. But as soon as I replace it, everything goes back to normal.
As you can suspect, this is getting a bit ridiculous and expensive.

I'm curious if it could be my ECM having some type of short and slowly killing the TPS? Or could it be the MAP sensor?

Also, just this morning I was driving on the highway and my speedometer died and there was no more overdrive. After restarting the car everything was back to normal.

Any help would be much appreciated, thanks!

bigal55

iTrader: (1)

For the TPS problem, have you measured resistance on the "bad" TPS? How does your TPS connector look, any wires pulled back or are the contacts in the connector corroded? Could be, every time you change the TPS, you get a better connection for a while then gets all corroded again or could be the pins are loose.
The speedo in your car is driven by the VSS Buffer, I believe. The buffer feeds the speedo, ECM and cruise control module (if applicable) so no speed signal to the ECM so no TCC lockup. Overdrive in a non-electric trans is just another gear so that should have been ok. HTH!

legendaryhero7

I haven't measured the resistance yet, I'll take a look at that tonight. One thing that does intermittently fix the issue when it's just starting to act up (not as many symptoms) is to disconnect the battery for about a minute. It will then act normal for a couple of start ups.

As for the speedo, are you saying it's more likely the VSS buffer? Is there a way I can check that?

Thanks for your reply!

bigal55

iTrader: (1)

I looked at the electrical diagram for your car and I see there is no buffer like the 8 cyl. cars, your VSS connects directly to your ECM and then the accessories get their signals from the ECM so, yes you could have an ECM issue (not necessarily a bad ECM). Check all your cables for good grounds and good clean power connections. When your car exhibits the ruff idle and sputtering, get a voltmeter and read the voltage at the TPS. You will need a small wire to probe the connector with the TPS still connected. You should have about 5 volts dc across the TPS and about 0.55 volts dc from ground to the center pin with the engine at idle (closed throttle). The 5 volt is supplied by the ECM as sensor reference. If you find you do not have 5 volts at the TPS, you will have to check your connections at the ECM. AustinThirdgen.org has good wiring diagrams and ChevyThunder.com has a lot of good info for help with troubleshooting various problems. HTH!

legendaryhero7

Ah, that's definitely good to know. I didn't get the chance to check the TPS last night, but I'll definitely get to it tonight. Thanks for the 2 links!