airaiboi808
New member
my 2004 pontiac grand prix gt...is loosing power. When I am on the freeway it feels like it's sluggish and when i step on the gas sometimes it doesn't downshift. also every now and then the temp gauge seems to indicate overheating then it drops down...i check coolant and its okay. also the o2 sensor is bad and I haven't done a tuneup on the car...like spark plugs and wires. could all this contribute to the car running sluggish? Oh yeah and I also replaced the mufflers with performance mufflers.