Ongoing mystery problem, anyone care to help?(long!)

Ok, a little background, I've had this car, a '97 Olds 88, for a year and a half. It had 101,000 miles on it when we got it. The first 11 months we had the car, it ran PERFECT. Not the slightest bit of trouble.
Then the engine light came on. Had it checked, they said it needed a tune up and an o2 sensor. They were getting ready to do the tune up and told me I had a problem with my engine, said the gasket under the upper intake manifold was bad, and I had burned-on antifreeze on the engine. Took it to someone else for a second opinion, he said same thing. Replaced that.
Not too much later, the car started accelerating on its own. Shift from park to drive, take your foot off the brake, and it GOES. It actually went up to 55mph, and held steady there. Push on the brake, and it was stiff, and when you let go it would push up with some force. Took it to mechanic that did engine work (reputable mechanic and an honest guy, good reputation in town) and he determined it was the throttle positioning sensor (TPS). Tried lubricating it, didn't help for long. Replaced it. Helped for about a day. Engine light still coming on, still accelerating, although not as bad, barely noticable, quits doing it after it's warmed up. Engine light code now indicates master intake. No problem detected there. Mechanic takes my car for two days and checks everything he can possibly think of. Nothing solves the problem. He's now completely stumped and doesn't charge me.
Now he's thinking it might be the computer. Hates for me to have to spend that kind of money, goes over car again (for free) still can't find anything. I wait a while to see what happens (and because I can't afford a computer) and it idles high (2000 rpm) when you start it, but once the engine is warm it drops to 1000 rpm and is fine for the rest of the day. Cold start in the morning and it's at 2000 again. Mechanic suggests I take it to the dealership. Dealership has it on two occasions, charges me an arm and a leg, and says the code they are getting is for the TPS. But, of course, there is no way to check that part. $200 and I still don't know what is wrong with the car.
Husband drives it 12 miles, it sits for a couple hours, and he gets in it to come home. Idling high so he lets it warm up, still idling high. Puts it in gear and it hesitates and doesn't want to go. Then he smells antifreeze burning and borrows a car to drive home.
Now it's sitting at my mechanic's shop, he hasn't had a chance to look at it yet but is pretty much stumped from what I've told him.

Any ideas??

Forgot to add, in the past month it has stalled twice, both times I was going very slow (drive through at McD's) and it made a sort of hiccup and then stalled. On three occasions in the past month it has refused to start. Turn the key and the radio comes on, but nothing else happens. Engine doens't try to turn, no click, nothing. Wait about 5 minutes and it will start.

My car (94 LSS) would idle high (2000 RPM) when started cold. 5 min. later, idles fine. Also it would stall on me occasionally when coming to a stop. Tested the TPS for the correct ohms. Was bad. You have to gentle with it when installing it. Maybe yours is bad again. Also check fuel filter, pump, and pressure regulator.

Thank you. I will stop by the shop today to see if he's looked at it yet. I need to get some stuff out of it anyways. I had been wondering if maybe I just got a defective part, or if it could have gone bad already for whatever reason. Thanks!

Let me know what happens.

Ok, a little background, I've had this car, a '97 Olds 88, for a year and a half. It had 101,000 miles on it when we got it. The first 11 months we had the car, it ran PERFECT. Not the slightest bit of trouble.
Then the engine light came on. Had it checked, they said it needed a tune up and an o2 sensor. They were getting ready to do the tune up and told me I had a problem with my engine, said the gasket under the upper intake manifold was bad, and I had burned-on antifreeze on the engine. Took it to someone else for a second opinion, he said same thing. Replaced that.
Not too much later, the car started accelerating on its own. Shift from park to drive, take your foot off the brake, and it GOES. It actually went up to 55mph, and held steady there. Push on the brake, and it was stiff, and when you let go it would push up with some force. Took it to mechanic that did engine work (reputable mechanic and an honest guy, good reputation in town) and he determined it was the throttle positioning sensor (TPS). Tried lubricating it, didn't help for long. Replaced it. Helped for about a day. Engine light still coming on, still accelerating, although not as bad, barely noticable, quits doing it after it's warmed up. Engine light code now indicates master intake. No problem detected there. Mechanic takes my car for two days and checks everything he can possibly think of. Nothing solves the problem. He's now completely stumped and doesn't charge me.
Now he's thinking it might be the computer. Hates for me to have to spend that kind of money, goes over car again (for free) still can't find anything. I wait a while to see what happens (and because I can't afford a computer) and it idles high (2000 rpm) when you start it, but once the engine is warm it drops to 1000 rpm and is fine for the rest of the day. Cold start in the morning and it's at 2000 again. Mechanic suggests I take it to the dealership. Dealership has it on two occasions, charges me an arm and a leg, and says the code they are getting is for the TPS. But, of course, there is no way to check that part. $200 and I still don't know what is wrong with the car.
Husband drives it 12 miles, it sits for a couple hours, and he gets in it to come home. Idling high so he lets it warm up, still idling high. Puts it in gear and it hesitates and doesn't want to go. Then he smells antifreeze burning and borrows a car to drive home.
Now it's sitting at my mechanic's shop, he hasn't had a chance to look at it yet but is pretty much stumped from what I've told him.

Any ideas??
Hello I'm Jon

I have a 1985 Oldsmobile Delta 88
The Carb is Rodchester Quadrojet
4bbl w/TPS

It died on me a few times, The Code we received was #21 which show as throttle positioning sensor, I'm buying a carb rebuilt kit and The TPS and having someone else more knawlegable than I Do the Job.

They want alot of Money for this carb

Ok, a little background, I've had this car, a '97 Olds 88, for a year and a half. It had 101,000 miles on it when we got it. The first 11 months we had the car, it ran PERFECT. Not the slightest bit of trouble.
Then the engine light came on. Had it checked, they said it needed a tune up and an o2 sensor. They were getting ready to do the tune up and told me I had a problem with my engine, said the gasket under the upper intake manifold was bad, and I had burned-on antifreeze on the engine. Took it to someone else for a second opinion, he said same thing. Replaced that.
Not too much later, the car started accelerating on its own. Shift from park to drive, take your foot off the brake, and it GOES. It actually went up to 55mph, and held steady there. Push on the brake, and it was stiff, and when you let go it would push up with some force. Took it to mechanic that did engine work (reputable mechanic and an honest guy, good reputation in town) and he determined it was the throttle positioning sensor (TPS). Tried lubricating it, didn't help for long. Replaced it. Helped for about a day. Engine light still coming on, still accelerating, although not as bad, barely noticable, quits doing it after it's warmed up. Engine light code now indicates master intake. No problem detected there. Mechanic takes my car for two days and checks everything he can possibly think of. Nothing solves the problem. He's now completely stumped and doesn't charge me.
Now he's thinking it might be the computer. Hates for me to have to spend that kind of money, goes over car again (for free) still can't find anything. I wait a while to see what happens (and because I can't afford a computer) and it idles high (2000 rpm) when you start it, but once the engine is warm it drops to 1000 rpm and is fine for the rest of the day. Cold start in the morning and it's at 2000 again. Mechanic suggests I take it to the dealership. Dealership has it on two occasions, charges me an arm and a leg, and says the code they are getting is for the TPS. But, of course, there is no way to check that part. $200 and I still don't know what is wrong with the car.
Husband drives it 12 miles, it sits for a couple hours, and he gets in it to come home. Idling high so he lets it warm up, still idling high. Puts it in gear and it hesitates and doesn't want to go. Then he smells antifreeze burning and borrows a car to drive home.
Now it's sitting at my mechanic's shop, he hasn't had a chance to look at it yet but is pretty much stumped from what I've told him.

Any ideas??

Hello I'm Jon

I have a 1985 Oldmobile Delta 88

my Carb is a Rodchester Qaudrojet 4bbl w/ TPS

it started to die while driving on the HWY so I've had to hope and pray to get to a safe area but my friend did a code check on it and the code was #21 Throttle Posioning Sensor and I was told you can take 1/4 cup or less of tranny fluid it will help klean the carb but will smoke for a while I hear !

will do

Well mechanic finally had time to look at the car (we can't afford to fix it right away so we told him to take his time) and discovered that there's 2 problems. The problem my husband experienced was due to a freaking engine fire! Luckily not a big one, but still! He said it looks like some sort of cleaner was sprayed and ran down the engine. I'd only driven it on short trips around town, but when DH drove it, he went far enough for the engine to actually get hot, and that crap ignited. The spark plug wires were all burned and melted. Good thing he pulled back in the driveway right away, that could have been really bad! So the plugs and wires have been replaced, but it's still idling high. He's thinking the TPS may have been defective to start with, as the car only ran right for one day after the new one was put in, and since it tended to run right after the engine was warmed up, and they already drove it before I picked it up, that would explain that. sigh. I really hate cars!

Amber