SeniorXJ

Today she started misfiring, had loss in power & the check engine light came on. Went to autozone & the codes read random misfires (P0301, P0300, P0305). Pulled the plugs and the porcelain is burnt on just one side on every plug. She's also starting to smell like gas. Can anyone take a stab at this & offer some insight? Being that the plugs are burnt on just one side, my thinking is a fuel injector issue? Running rich or lean possibly??


Important note: the head was just done 1500 miles ago and EVERYTHING is brand new!! Plugs, wires, cap, rotor, and ignition coil. Also 3 different sensors and a fuel pump. Made an appointment with the guys who did the work, but that's not till Monday. I'd really like to figure this out a lot sooner so all advice is welcomed!!

SeniorXJ

Adding photos. Remember these only have 1500 miles on them. (NGK V-Powers)

CCKen

Those plugs are normal. Check the gap (.035") and reinstall. If the gaps on those plugs exceed .035", pull the others and check the gap them.


That flash you see is also normal. That's the side of the plug facing the exhaust valve.


With a gas smell you are running rich. Running rich can be caused by leaking injectors, defective O2S', exhaust leak upstream of the upstream O2S, coolant temp sensor, high fuel pressure, or base engine issues like incorrect timing. problems

SeniorXJ

Got any ideas on how to narrow that down & diagnose the problem?

exasemech

1) the only things I would add to Ken's note is the possibility of an electrical injector issue ,( like a bad ground to the injector harness or nicked/mouse eaten wire). In theory the "car parts store" tool would see a code for that, but....(story here) I got a 2000 XJ last fall, CEL was on, seller told me he took it to where ever and they told him it was a misfire and he needed a new coil rail which he didn't buy. When I got it home I cleared the code which soon reset, hooked up my scan tool (I have 3, OK, I'm weird) was a misfire code, but when got deeper into codes it showed an injector problem , traced it to a loose ground.


2) If it's misfiring bad enough the gas smell could be just the unburned fuel from the misfire that's getting through the cat


3) As far as tracking down the problem, do it system by system. I would start with the ignition as Ken pointed out; stuff like are the cap and rotor Ok?, wires on and tight etc etc.
If the thing has been apart recently and a bunch of sensors replaced a loose connector is not unlikely although that too should set a code.






4) hard to tell from a picture but the plug gaps look huge. "IF" they are, that can be tough on the ignition secondary and coil.


5) Not picking on the original poster as he has a lot of company but BUY A DECENT SCAN TOOL ! They don't cost that much and you can't work on stuff without one. Get one that gives you at least some live data. ....and no, you don't need three


Good luck. Let us know what it was when fixed