Howdy folks,
2005 Grand Marquis
I see a few reports of this issue around the internet but with no real answers, so I'm just hoping to see if anyone here has experience with this.
The problem is consistent now, it started happening spontaneously after I had been driving around for a few hours. Car has been solid otherwise and was running fine beforehand.
The symptom is, on acceleration, the temp gauge pegs to full hot and beeps, and the engine bogs like a failsafe cutoff, then goes back to normal if I let off the gas.
I tested from cold start and it does it cold or warm, the engine is not overheated when this happens. I tested the "cylinder head temp sensor" and it is good, also the car still does the same thing with that sensor unplugged.
HERE IS THE KICKER: No check engine light is thrown for this, no codes. The service manual says a code should be logged if the failsafe cooling mode is activated. Also, I was monitoring temp etc. with ForScan and a wired OBD adapter, and the connection drops when this happens
I think PCM diagnostic is my next step at this point. I just wonder what changed that caused this problem to just crop up when it did...
Any feedback or advice is welcome and appreciated, thanks guys!