Ugh, if it isn't one problem, it's another it seems like. I've had this car now for 8 years. 2003 pontiac grand am GT. First, when my car is not moving as in in park, or at a light, it has a SUPER rough idle. It calms down if I switch to neutral. Trying to keep as much pressure off the engine as possible since I have had more than 5 internal engine issues. Next, my car heater doesn't work unless I am consistently accelerating. Like when I'm on a highway. Now recently my car is trying to overheat when I'm not accelerating at all. But as soon as I take off, the heater kicks in and the engine cools off and is at normal temperature. Today, I was getting on the highway on my way to work and the heater was working, but then, all of a sudden it goes cold and the temp slowly started to rise. As I exited, it steadily got hotter and by the time I was able to park It was almost in the danger zone. ODDLY when I put it in park the temp went down. Then while in park I slowly accelerated the gas and the temp went down and the heater started to work. I know a lot about my car internally especially. I've never had an issue like this. I want to say it is the temp sensor that is causing the overheating, but I'm out of options with the heater and the ROUGH idle. Btw, my service engine light is one. Shows it is cylinder 2 misfire. But that's been like that off and on now for years. Even with new plugs and all. ANY help would be very helpful and appreciated!
Heater only works at consistent gas acceleration + overheating at idle
- Thread starter Nikki87
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when is the last time you checked the codes on the computer, if you get new ones without correcting them you are leaving yourself open for problems. When the engine is running hot do the fans come on? Have you tried replacing the thermostat? Have you pressure tested the cooling system? Are you low on engine coolant? Have you bled the air out of the cooling system? If the code you had in the past was P0302 did you check the causes listed on this link?
http://www.obd-codes.com/p0302
http://www.obd-codes.com/p0302