Yesterday on my way home from work, I went to pass someone, and my truck hesitated a little, my engine light started blinking, and my a/c started blowing hot. I slowed down, and the engine light went off and my a/c started blowing right again. Truck ran fine the rest of the way home. I can't check the code, because the light isn't on anymore. Anyone have any ideas? Strange that my a/c started blowing hot for a second. I'm stumped. Thanks in advance!

 

My truck did that last year....it was a COP (coil on plug) that was acting up. I think that if a check engine light comes on it will kick out the ac compressor. It would start up fine and drive ok until I would go a constant speed for a bit then try and accelerate it would act up.

 

This happened to my wife's car (merc. milan) and it was a COP problem. Somehow it got wet from an automatic carwash, and caused a misfire.

However, I'm surprised that your light didn't stay on if this was the case. Interesting......

 

I had the same thing going...my CEL wouldn't stay lit for a week, then finally threw the code while I was on a trip. It was a COP. Even though it specified the cylinder, I went ahead and replaced all 8...got them from Global Auto through eBay...

 

A flashing check engine light is a misfire.

Check for codes anyways, the misfire monitor is probably the most sensitive out of all the monitors since it has to watch over things to protect the converters. It may have a history code stored.