My 2012 FXT has been throwing fits in the past few weeks. The vehicle runs fine on the highway or around town. Gas mileage is good actually seems to be improving. But, if the car is stopped when hot, allowed to sit a few minutes and then re-started, it coughs and sputters and acts like the world is ending. It also throws P030n codes (this morning's edition was P0301 and P0303, but it's also misfired on one cylinder and on all four cylinders. If the vehicle sits for an hour or so, it starts and runs just fine.
I've been checking likely causes, but so far have not found the problem:
- I cleaned the MAF - but not really that dirty.
- I've got new NGK LFR6AIX spark plugs to install, but the NGK [email protected]" plugs in the engine only have ~25k on them.
- I removed and cleaned the purge valve, but it seemed alright - nothing obviously wrong Are there other valves that could upset the fuel system?
- I've been looking for vacuum leaks, but so far have not found anything major or likely to cause a problem.
The engine acts like some system or valve is no re-setting properly, or maybe it's failing - on it's last leg - so hot re-starts are a disaster area. Once the engine starts and runs a bit, then the only reminder is . . . the P030n CEL codes (steady, not flashing).
Suggestions? Thanks
I've been checking likely causes, but so far have not found the problem:
- I cleaned the MAF - but not really that dirty.
- I've got new NGK LFR6AIX spark plugs to install, but the NGK [email protected]" plugs in the engine only have ~25k on them.
- I removed and cleaned the purge valve, but it seemed alright - nothing obviously wrong Are there other valves that could upset the fuel system?
- I've been looking for vacuum leaks, but so far have not found anything major or likely to cause a problem.
The engine acts like some system or valve is no re-setting properly, or maybe it's failing - on it's last leg - so hot re-starts are a disaster area. Once the engine starts and runs a bit, then the only reminder is . . . the P030n CEL codes (steady, not flashing).
Suggestions? Thanks
► The latest Update can be view here on post #48.