Thread: Car boggs, wants to die when giving gas.

Hello, I have a 1990 model with only 100,000 original miles. The previous owner took pretty good care of it. It was running great untill about two weeks ago. It idles fine, and drives if you barely give it gas. Once you step on the gas, it boggs down, and barely goes. It even bogged, and cut off once. I have changed the
Fuel injectors
fuel pump
fuel filter
maf sensor
air filter
oil, oil filter
and idle air control. I checked the fuel pressure, and it was normal. The coil pack was also changed before I got it. I took it to someone to read the codes, and he said he didn't get any? My brother said he checked the comp and fuses, and that was all fine. The only thing I can think to check is for a vacuum leak. What do you guys think? Thanks.

Thanks for the reply. I changed out the gas, when I put in the new pump. Also used high grade. I couldn't find a vacuum leak, so i'm gonna test the cats pressure next. I hate thinking about how much i'll get charged, for someone to wield a new one in.

hey have you fixed this car yet? i just got one that does the same thing and need help fixing. it seems like no throttle responce but i changed out the TPS, fuel pump, filter, and pressure reg. it will rev up about the first 30sec but then the problem starts.

Not yet. No vacuum leak, and the cat checked out. Maybe a broken wire or grounding prob somewhere? A GM mech is gonna look at it this week, I'll let you know what he finds.

Hey, I have been dealing with a similar problem for two and a half years and fixed mine just last night.
The problem was the upstream O2 sensor. I have a newer 3.1 but I believe they are set up very similar. There is an upstream and a downstream O2 sensor, one before and one after the catalytic converter. The one downstream, after the converter, is just for emissions purposes. The upstream effects how the car runs by detecting the amount of oxygen in the exhaust gases and adjusting for peak performance and fuel economy. The best way to test it would be to just unplug the sensor and drive the car to see if it runs differently, it will either run the same or it may even run better if it is bad. The reason for it running better would be due to the computer switching over to a loop cycle or rich cycle because of it detecting there being a problem with the sensor. The sensor is located behind the engine, about in the center, tapped into the exhaust manifold. For me it was easier to go from the top of the engine, but the sensor has 3 or 4 wires coming out of it with a clip that plugs into the wire harness. My clip was kind of a bugger to unhook and be careful not to rip the wires out, but just unclip it and tuck the clip somewhere so you do not melt it on the exhaust manifold when you drive it.
Let me know if this helps.

ok i will try this tomorrow and let you know what happens

Originally Posted by Donut75

Hey, I have been dealing with a similar problem for two and a half years and fixed mine just last night.
The problem was the upstream O2 sensor. I have a newer 3.1 but I believe they are set up very similar. There is an upstream and a downstream O2 sensor, one before and one after the catalytic converter. The one downstream, after the converter, is just for emissions purposes. The upstream effects how the car runs by detecting the amount of oxygen in the exhaust gases and adjusting for peak performance and fuel economy. The best way to test it would be to just unplug the sensor and drive the car to see if it runs differently, it will either run the same or it may even run better if it is bad. The reason for it running better would be due to the computer switching over to a loop cycle or rich cycle because of it detecting there being a problem with the sensor. The sensor is located behind the engine, about in the center, tapped into the exhaust manifold. For me it was easier to go from the top of the engine, but the sensor has 3 or 4 wires coming out of it with a clip that plugs into the wire harness. My clip was kind of a bugger to unhook and be careful not to rip the wires out, but just unclip it and tuck the clip somewhere so you do not melt it on the exhaust manifold when you drive it.
Let me know if this helps.

Hey, Thanks man. The one mech I dealt with, said a bad 02 sensor would always show a code, so that couldn't be it. I bet your right, and that is it. I'm gonna take it off tomorrow. Thanks man.

ok so checked and this gp has a single wire o2 so that wasnt it. now i went and got another memory chip and installed it and it runs fine.
now the problem sounded the same as yours so i would sugguest you try the same. got this one out of the comp of another gp. its inside the cover thats held on with 4 little bolts. good luck and thanks for the help.

yes i agree. something did spike past the parameters to burn up the chip. that does need to be fixed so it does not happen again.

Unplugged the 02, and it was the same. A friend of mine said he would wield a new cat in for me, that his car did the same thing. If thats not it, i'll look at the chip. I'll keep you guys updated.

Gonna replace my Cat in the morning. I will cry if this doesn't fix it lol. I'll let you guys know what happens.

Ok, changed the cat, and that wasn't it. I did find two hidden vacuum leaks and fixed those. It runs better, but still boggs/wants to cut off. Now we are looking for any other vacuum leaks, or a broken wire. There has got to be something we don't see.