Pontiac Repair: My Grand Am Stalls, neutral auto, pontiac grand am

Question
I have a 1990 Pontiac Grand Am SE, 2.3L Quad 4 DOHC. If I run the car for a quick run it works just fine, however if I go for more that 7-8 miles than the car will lose power and stall out. If I quickly put the car in neutral (auto trans)than she will regain power and not stall but as soon as i put it back in drive it will have no power and stall out. Than I have to leave it for 4-5 hours and go back and then I can make it back home. I was told it was my battery but I just replaced it with a new battery and the car still stalls out. The car does not overheat or anything and if I run the car in park or neutral it will run all day long without any problems. Only stalls out when she's in drive or reverse! Just wondering if you have any suggestions? Thanks!

Answer
It could be several things causing your problem. A fuel pump that is going bad, ignition parts failing due to heat, etc. The best thing you can do at this point would be to take it in to the shop and have it diagnosed before you start throwing parts at it.