I have an 05 mustang only mod is an mrt exhaust. While I was driving home tonight I noticed my check engine light was on and when I turned off the car I haeard a slight hissing sound coming from the passengers side of the engine compartment. I popped the hood and looked inside all the lines looked fine and the engine ran fine any ideas to what might be causing the problem? Also anyone know how much it usually costs to have someone run an engine diagnostic check? thanks.

 

Not sure but im guessing you have warranty -- take it in and have them look at it and it should more then likely be covered.

 

Probably just one of those damn sensors in the engine (they only use like a jillion of them).

 

Hissing sound? Check your coolant level.

 

was the AC running? Hiss is probably water evaporating.

The light should not be related. Get a code scanner if you are out of warranty and see what comes up.

 

ya I will probably end up getting a code scanner. Andy yes I was running the A/C but I have before and there usually isn't any hissing sounds.

 

Hi, the hissing you heard was water dripping on your hot exhaust pipe from the air conditioner.evap can.(you may have been parked on enough of a tilt for the water to hit the pipe someplace.as it usually misses the exhaust pipe as it drips )Also LOOK under the passanger side kick panel for a water leak that gets near the computor there.i had one on my 05 mustang and the water will short out the computor causing all kinds of trouble.mine turned out to be a small leak where the floor meets the wheelwell.a small gap was left and water was entering from there.(good luck)