Car lurching, tech said maybe throttle switch, does this make sense?

[tcman49]

My 2001 Grand Prix GTP, 80K miles, no mods, has picked up an annoying habit of lurching after I get off my 1 hour high speed expressway drive. Going thru downtown then to my house at about 35-40 mph the car is lurching badly mainly when I accelerate from a stop. The engine light does come on, after the car sits in the garage overnight and maybe after one short drive to my workplace the next day, the car drives fine and the engine service light isn't lite anymore. (At high speeds on the expressway the car drives fine)

I brought the car into an exhaust shop and had the cat tested, thought it was clogged, they did the test and said it was fine. The exhaust guy not really being an engine guy said he had seen this before in a couple of cars, he said the problem might be the throttle switch, does this make any sense to anyone?

thanks

 

[BillBoost37]

If it were surging, as in you have to hold it back with brakes and it's trying to get away from you at lights etc. That's common of a TPS. Lurching though sounds like you are driving and all of a sudded it jumps.

 

[tcman49]

If it were surging, as in you have to hold it back with brakes and it's trying to get away from you at lights etc. That's common of a TPS. Lurching though sounds like you are driving and all of a sudded it jumps.

When I accelerate the car is fine initially and then its like the engine almost dies and then it picks back up, once up to like 40 or 50mph, the car is fine.

This only happens after a long high speed expressway drive, its like something is getting hot and some sensor is retarding acceleration to protect the engine or something.

 

[98gtp]

Get the engine code checked. My parents buick regal had a similar problem and it was the mass air sensor needed cleaning.

 

[BillBoost37]

Oh...yeah, that is likely the knock sensor. Odd how it does that huh?