Recently my car has been acting strange. Sometimes on the start up the car will act like it wants to die and the rpms will drop very low, but it will usually catch itself and be fine. I can keep this from happening by giving her a little gas after starting her.

Another strange thing that happens randomly, while waiting at a light, my temp gauge will shoot to max hot and I'll get a engine temp warning on the dash info. Once the temp gauge moves all the way to the max hot, it will go right back to the middle of the gauge and the dash warning will turn off. This also sets off an engine code. I've tried to read the code with my SCT, but it gives me an "error reading code" message.

I've dropped my car off at my mechanics and left it for him to drive for a couple of days and of course everything goes smoothly.

Any Ideas? Faulty temp gauge? Leaking head gasket? Air in the coolant line hitting the temp gauge?

 

My guess would be air since the temp rises and falls so fast. I'm not sure how you purge your water jacket and heater.

 

should be self purging since the overflow tank is above the level of all water in the system.

 

The second problem could be t stat sticking shut for a few seconds.And the first problem try when your starting when it sits for awhile turn the key to the on position for a few seconds till the fuel pump primes the line then start it! Had this problem before with my other stang, Sometimes when sitting over night the fuel can bleed down from the line,So when just get into the car and start it there is not enough fuel in the line for a few seconds.

 

Going to get the code read today. I'm hoping its just a T-Stat malfunction

 

Do you have the code #?

 

Nope, couldn't get anything to read the code. tried an sct3, sct2, predator, and some other big gizmo.

 

There is no sensor in the coolant line, so that's not it. The ECM guesses on the coolant temp based on your head temp sensors. it sounds like a faulty sensor, but which one, idk.

The stumble when starting, does it do it first thing in the morning? Mine fires right up first thing in the morning, but when I go to leave work it will sometimes do the stumble, then rev up a little, then settle to idle. Cleaning the MAF sesnor will fix it for a while, but it always returns. When I first start my car every day, it fires up like it has something to prove. I don't get why after sitting for 8-10 hours it will stumble, but then the next morning it fires up like it's pissed at the world.

It's almost like the ecm thinks the engine isn't cold, but then it realizes it's mistake and tries to recover. Mine has never stalled by the way.

 

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How about the water thru the firewall problem? Is your passenger side floor wet? That could make all sorts of problems...