Thread: 2000 Grand Prix Hard starting and dying/Cutting out when on throttle, whats the cause

I bought a 2000 3800 GP a week ago from a guy who took it away from his daughter. Has 177K on it and bought it for $375, It started right up and drove on the trailer. He had cut the Cat off it for Scrap, so when I got it home I put a piece of pipe on it and unplugged the 02 sensor that goes behind the cat. It ran and drove good for several days and put about 40 miles on it with no problems, until yesterday.
I filled the car full of gas and it started to rain out and I drove it 7 or 8 blocks in the rain and started running ruff/cutting out and died, it would refire but acted like it was flooding itself out when I would push on the gas and would run briefly and die. I let it sit a day, started it up and it idled fine for a couple minutes, but when I put it in gear it would die/ cut out, same as when I pushed on the throttle.

Could this be a bad Throttle position sensor?

Or is it caused by not having the cat and the sensor unplugged? I had a 96 3100 GP that I cut the cat off and replaced with a pipe and unhooked the 02 sensor and drove it 4 years without a problem, I also had a couple 97-2001 GTP's that I cut the cats and exhaust off and raced on dirt and never had a problem.

Or could it be something else?

Originally Posted by Slick2500

Plugs, wires, fuel and air filter.
You could have just left the rear o2 plugged in, its not going to hurt anything and its going to throw a code being unplugged anyway, I doubt that has anything to do with your issue.

Thanks for the info, those are on my list to change, hell it might be a plugged fuel filter, I just didn't know if it could be the TPS sensor or not.
The guy cut the pipe to close to the back sensor for me to get a pipe hooked up to it no problem so I had to cut it off and unplug the sensor.

I had another TPS sensor laying around from a car that ran fine 2 years ago, I installed it, and it starts fine the first time and idles fine, but the second you touch the throttle it cuts out and dies. I had it sitting there idleing for 3 minutes it idles fine and all of a sudden it started running rough and died.
I also noticed that before I filled it with gas the heads up display worked fine and registerd fine, now since I filled it full, it reads 0 for all the fuel range and the average economy, it does register that I have used 0.3 gallons since filling up.

I plan on putting a new fuel filter on it tomorrow when the parts store is open, maybe it's plugged? It looks like it's been on there awhile

Any other thoughts on what it could be? I wouldn't think the crank sensor since it does start, but could it be? I don't know **** about any of this new electronic fuel injected stuff.

Have you cleaned the TB??

Sorry guys been busy with work and haven't had time to give a update.

I changed spark plugs first, and that didn't change anything, so next I had a friend stop over with a scanner hooked it up and it had 6 or 7 codes in it, I cleared the codes, and it started right up and ran normal with no problems.

Since then, I drove it about 80 miles with no issues, other than the service light coming on which I figured it would due to not having a cat or rear o2 sensor. I hooked the scan tool back up after 80 miles and it had 3 codes:
P0108: MAP Or BARO Pressure Signal High
P1106: MAP Sensor Circut Intermittent High
P1811: Maximum Adapt & Long Shift

I presume those first 2 codes mean that I need to replace the MAP sensor? Would the Map sensor cause the problem that I had? I have driven the car about 400 miles now with no issues runs fine.