ok well my 04 grand prix with the 3.8l na seems to be overheating when going up large hills. i got this thing with a ton of problems. so far ive replace the head gasket with rebuilt heads, new radiator, new tranny, new thermostat, new water pump, flushed the cooling system. the radiator fans are working correctly. it not using any water and has no water leaks. the head gasket isn't leaking and it never overheats normal driving, just when you go up a 10 mile hill. im thinking maybe my cats clogged anyone have issues with the cataltic converter my car only has 120k. any input would be helpful. i guess you only pay 1000 buck for a reason. oh by the way i wasn't with the car when my woman was driving and she pulled over when it got to 3/4 of the way up the temp guage. i guess she also said it seems to have a loss of power no check engine light
