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Sorry for the quad post...

Found a couple of disconnected vacuum hoses behind the engine while getting the back valve cover gasket done.

It's running ok for right now. However a P0121 and P0122 popped up now for the throttle position sensor. I made a big mistake and tried cleaning it with MAF sensor cleaner.... Now I cannot get a reading at all with my scan tool...

I fooked up. Going to get another TPS...

I would have thought it was OK to clean with TB spray too.

Turns out I installed the tps wrong lol. It's giving me a signal now. I have a p0121 again, But the car runs fine now except it shifts bad during high throttle which I'm blaming on the sensor or the connection.

Gah I'm about ready to drive this car into the giant shredder at work!!

The P0121 went away, But now it's running just like before just random hesitation and fluttering...

Luckily now I have a good feeling the root problem is something with the tps or what connects to the sensor. Going to clean out the TB out tomorrow to see if that helps and check the wiring. I hope I can get this *shoot* figured out soon.

Since then I've cleaned out the throttle body and replaced some vacuum lines that kept falling off. For the past couple weeks the car will run mostly fine now. No more hesitating upon acceleration in either open or closed loop.

Not out of the woods yet though. When letting off the gas pedal sometimes the RPM gauge will go down to about 500 and struggle until I accelerate again. Also a few occasions after it struggles the car will idle at 2500 RPM by itself! This ONLY happens when the P0121 CEL code is on. Otherwise the car runs perfect.

To get this fixed I'm probably going to take it to a shop. All that's left to try is a wiring/short issue or a bad PCM. I'm nowhere near inclined enough to test lol.

Wouldn't it be cheaper to just replace the TPS with a new one than to take it to a shop?
Rockauto has them for $52 OEM and less, plus you get a 5% discount as a forum member.
A bad TPS causes problems because the computer can't accurately determine how much fuel the engine should be getting (and other things). That's why you're idling at 500RPM one minutes and the next time you idle it's at 2500 RPM.
Symptoms of a BAD TPS:
There are numerous issues that can result from a defective TPS. These symptoms can range from rolling-idle, engine stalling, a no-start condition, rich (heavy fuel) or lean (low amounts of fuel) conditions, higher than normal emissions, erratic acceleration, to poor shifting performance in an automatic transmission.
Excerpted from http://www.enduringautomotive.com/tps/

I did.

It looked like you were going to replace it but then discovered you had reinstalled the cleaned TPS wrong.
You can check the TPS wiring by following the steps here: http://easyautodiagnostics.com/gm/3.8L/ ... n-sensor-1
Though unlikely, it is still possible that the replacement TPS is defective.
As a final step before condemning the ECM, clean up the grounds on the battery, engine and the buses that are under the carpet by both front kickpanels?