I have a 1989 Pontiac Bonneville LE with 129678 and a few months ago it had a bad radiator, it was getting way too hot. So I replaced the radiator and everything was fine for about 5 minutes. I took it out on the road and it shot up in temperature all the way to the top past red and i stopped it and it started pre-igniting and then it stalled. Now anyone knows, thats a VERY bad thing. Never did find out why that happened. So I got it home and added more coolant/water mix and then everything was fine. So now the real pain in the neck starts. It started surging and then stalling, but once you got it going everything was fine, and that graduated into where the car would idle very nicely and totally out of the blue just stall as if somebody had shut it off. So then this graduated into the check engine light intermittently illuminating and shutting off. Now a few days later I was driving along on the freeway about 70 and all of a sudden it stuttered like it wanted to stall, but it was with alot of resistance as if someone had hit the brake, now im not stupid, i know it was because it was in a driving gear. But then the light turned on. And then everything was fine again. But then it would do it again and the light would come on about 5 seconds after the jolt. So I checked the engine codes and got a whole mess of codes. The codes stated that the TPS was grounded WOT and that the MAF Sensor was sending incorrect voltage. Now the MAF sensor being as expensive as it is, I wanted to replace the TPS first. And then I did and everything was OK. But then it started surging again, and I put it into a drive gear and it moved so all was well untill I went to get on the road. The SECOND I pressed the gas to accelerate onto the highway, it choked, stuttered, sputtered, and stalled. And all of this was happening while it was surging. So I decided that it was the MAF sensor that was causing all my grief. So I went to a salvage yard, saved $100 and put one on from a '90 Buick Regal with 267765 miles on it. The engine had like blown something and so that fixed the problem of the car acting like it was drunk. But the light stayed on and everything was fine. But the next morning I started the car @ 6 am @ 39 F. And it went STRAIGHT to 3500 RPM and stayed there. I let it idle there for 10 minutes hoping that it would lower and eventually had to shift. Now I know how bad that is for the transmission. I could feel the torque converter wanting to kick me, but once I drove for a while it would idle at 700 where it is supposed to. I have adjusted the TPS 6 different times to try and correct this, but everytime it shows the voltage is correct. I am now ending this novel by asking with my deepest hope that someone will know how the heck I can fix this.

Sounds like your problems started after the car overheated a few months ago. I'd check the engine compression & hopefully you can eliminate any serious problems. Are you still getting trouble codes?

Compression is fine, car drives fine, but I am still receiving that code 21 for TPS maladjustment.

could your accelerator cable be sticky maybe? throttle plate and everything gummed up?

Is it possible you have a bad or sticking IAC? Sticking throttle plate?

its funny you would mention that, RECENTLY, everytime the car has been shut off for even 5 minutes the accelerator pedal feels like it froze in place. But once you have it broken, it works perfectly. But you can break that and it still doesnt readjust. ALSO,why would it be giving a code for stickyness? FYI, i am not positive what adjusts the throttle in this car, but if it she save vaccuum that the Cruise Control uses well that could be a problem, the cruise control servo is bad, i am not sure but it is possible....also, the vacuum hose, the one that connects to the top middle of the front valve cover..well it has a broken gasket, it is just sitting in the hole. Could that be an issue with anything? It only has been broken since I had to get to the TPS on the front of the throttle body. The hose was blocking it and so i moved it and it popped out.....pls help

If your throttle cable is sticky, it'll leave the TPS in an unnatural position. Try disconnecting the cable on the cruise control side to make sure that'* not what'* binding. Otherwise, chase down the sticky throttle.

Also fix that vacuum line asap. Vacuum leaks don't allow our motors to run very well.

simply locate the signal and ground wire on the TPS.
Tap into them with dig voltmeter, key on, engine off and check the voltage. 4.2 - 4.6v @ idle position.