My check engine light comes on and it usually reads Throttle Position Sensor.
This solves the problem, because the check engine light always comes back on.
Last changing the Idle Control Valve solved the problem and as always the problem comes back.

I can always tell when the problem is starting to act up, the car runs crappy and idles very low to the point of stalling.
The check engine light will come on the next day and the car will start with a high idle on the cold mornings. I'll put the car in gear to keep the idle down. I then sit and let the engine warm up. I then turn the engine off and restart the car. This usually gets the idle back to normal.

I wasn't able to fully understand what you wrote. Did you change the throttle position sensor?

I'd check the connections and wiring if so. It sounds intermittant.

I've changed the throttle position sensor a while ago, but not recently.
I have codes P1406 for the EGR and P0121 for the throttle postion sensor.

I'll put my money on a vacuum leak.

I had that same feeling.

That'* cool that you both have the same "feeling". From what I've read and seen, I doubt that TPS code can be tripped by a vacuum leak.

https://www.gmforum.com/showthread.p...ighlight=p0121

He said he changed the TPS, but it is possible it'* bad again. My thought is the low idle could trip odd codes, ie, idle does not match the TPS position. Vacuum leaks are also easy to check for and cost little to no money to do.

Idle is controlled by the IAC valve. If the TPS is closed it should read 0%.

I also know that running the car with out the pcv valve will trip the Tps.
The car isn't acting up at the moment, I'll look at all of the those things, but I just have little ambition to look at the car outside in the winter.

Stop on over. We can pull it into the garage.

FWIW I was in Worcester Saturday at 8am ... aka 1F degree, hitting up the junkyard.