2003 Pontiac Grand Prix Driving

Well your starting to get a lot of miles on your car so I would try a couple things. One you have 200+K miles are carbon build up inside your engine so I would first do a 3 part fuel system treatment cleaning of (Injectors, intake and throttle body) all that buildup if costing you fuel economy and hp. Change your air filter if its dirty more air is more power. Check your transmission fluid while its running, If trans fluid is too high or low you can get poor performance out of it. If you want your car to run another 200K miles I would also change the antifreeze and your transmission fluid every 3 years