There's been a new problem each week I've had my Jag, but I'm just chalking it up to growing pains.

A few weeks ago I got the code P0302 and P0303. Turned out there was a vacuum air hose leak and misfiring #3 coil. Replaced/fixed. $300. Not too bad.

Then restricted performance (but car drove fine). Cleaned mass air flow sensor, unplugged battery for 24 hrs. Fixed it.

Recharged battery.

Got oil change (non-synthetic 10-30) new filter.

Low coolant light. Filled it w/ green. Light disappeared.

Yesterday, suddenly started rough idling and I knew what was about to happen. Engine light... p0307 and p1316.

Gonna try to swap coils and look for oil puddling in the cylinder before taking it in.

Any other suggestions?

 

Coils are a wear item, heat (or oil) kills them, so you're OK though you could change them all if feeling rich.

I'd use 5W30 but just a thought.

Plugs were due at 10yrs (or 100K miles) if not done.

I'd fix misfire, then in a few days check fuel trims to see there's nothing lurking.

 

Thanks. Any idea how long coils are expected to last?

 

From one day to the end of the life of the car. It is hard to say.

 

I did not spend that kind of money when i replaced all 8 of my coilpacks. Swapping is a good test but it could be your plugs. How long have you had the car?

 

I replaced all 8 coils and plugs for around $300.

 

I've only had it a month. Apparently new plugs were installed last year.

How do you go about checking them?

 

You can pull and look at them and they are directly under the coil but for now I would swap the coil and see what takes place

 

Also remove one plug and see if it's the one specified for the car. There have been reports of misfire due to incorrect plugs.

 

Okay. I've just swapped coils. Put everything back together and started the car. its running rough as before. oh and I had cleared the codes before I switched coils.

should I just let it run long enough for the computer to detect faults?

 

Turns out that the ecu can take 60 miles to register a new code so I went ahead and bought a Duralast coil and exchanged it.

Immediate improvement. Engine was purring like a cat! So it turns out a cigar was just a cigar in this scenario. Used side bg 44k so hopefully things will only get better from here.