Lately my cars temp needle is hovering around half level, and it used to be at about third.when it goes to half my car starts to stumble and not run right. I flushed the system but no luck.Although at highway speeds it goes below half and runs good.My car never used to do this ,it started lately.Can some body help please???????

 

Actually half point is supposed to be factory. You may have a low temp thermo which gets your car to stay at the third mark. Its not a bad thing. When was the last time you changed your oil?

 

hmmm, I think you have a different problem. You might want to check your ECU for error codes.

S

 

 

I do regular oil and filter changes, I had this car for 3 years now, and the problem started about 2 months ago.

 

Have you been running the A/C for the past 2 months? That will certainly drive up the temperature.

-C-

 

I am getting the ecu code 55, and when i use the air conditioning it gets worse!!

 

Well, the code 55 means that all of the sensors that the ECU monitors are OK. My guess is that you might need a tune up, change your plugs, wires, cap, rotor, PCV valve, air & fuel filters, and adjust your timing and idle. I just did most of that to my car and it runs much better.

The temperature gauge needle in the middle is normal as Q mentioned (you're technically not overheating) and mine even goes beyond that when I'm idling and running the A/C. And since you've done a flush recently, I don't think there's anything wrong with your cooling system.

The A/C not only puts an additional strain on the cooling system (which might be why your temperature gauge is reading higher than usual), but it also saps power from the powertrain, which if your car isn't tuned up properly could result in stumbling, hesitation, and power loss, and it's especially noticeable when accelerating.

-C-