1999 Pontiac Grand Am Lurching

Hello,

For about a month, off and on, my car has been lurching when I drive. What happens is, when I start driving, as long as I drive over 15 mph I'm fine. But if I'm in a crowded lot or caught in traffic moving slowly, the car starts to lurch forward like it wants to move. This only happens sometimes.

Also, if I drive to work then back home hours later it rides smoothly both trips. However, if I go somewhere then start the car again a short time later, it lurches, makes revving noises, then tries to shut off. It actually has shut off on me 3 times (once while I was at a repair shop!). No one can figure out the issue.

One mechanic suggested I needed new spark plugs, but even after he replaced them about 2 weeks ago I am having the same issue. I have also heard it could be the transmission or the throttle body needs to be cleaned. I am open to suggestions, but I cannot afford to keep paying for things that are not actually fixing the problem :( Please help.

Thanks!
Shanna