Advice please,
04 Xj8, started it this morning and immediately noticed a miss fire.
Waited to let it worm up to see if it would clear up but it didn't.
Drove it around a while and noticed the temp gauge was barely moving upward.
Finely the needle got to the half way mark but still had the bad surge/miss fire.

Does this sound like a bad air temp or water temp sensor issue ?
Thanks for any input ..
Joe

 

It sounds like a plug/coil type problem. Did you get a check engine light on the dash? If you have code reader, plug it in, if not most auto parts stores these days will check for you. a P0--- code will tell which plug to check. Swap coils with another plug to see if the code changes to the other plug in which case it's your coil or remains the same in which case it's the plug.

 

Hello,
I just used a code reader, and got a message > P0305 cylinder 5 misfire detected .
It gave possible reasons for it.
1 bad injector
2 bad plug
3 low compression
4 bad coil
5 vacuum leak
6 cam sensor
With your experience with XJ8's are you leaning toward the coil as the culprit ?
Thanks

 

jbellK75,
I'm going to check the plug and coil conditions , also do do have any idea why the temp gauge needle took forever to reach the 1/2 mark ?
Thanks,
Joe

 

How llong is "forever" and what was the ambient temp? I personally wrote that bit off as a red herring and felt the same, that it's just an ignition issue.

 

My XJ8 experience is all of one week. I just got an '04 w/32K miles. I would try swapping the coils with your 5 plug first before pulling any plugs. If the code jumps to another cylinder than it's that coil that is bad, if not, then it's time to pull the plug, run compression test, etc. I don't know your experience level so don't take this the wrong way but if you swap coils make sure you swap the electrical leads as well. Keep us updated with what happens.

 

I concur that swapping the coil to see whether the error shifts to another cylinder would be the first step to do for me, as well.

Best regards,

Thomas

 

Update
re: How long is to long , normally the needle will get to the half way mark by the time I exit my neighborhood, I drove down to the gas station came back
and it was still only a 1/4 of the way up (20 mins +)
I pulled the plug on #5 to see if it was a oil contamination problem, Very Happy to see it looked Great !
Then swapped coils 5&3 and rechecked the scan tool it then said cyl #3 was bad which confirms what you guys said (Thank you ) !
I ordered a replacement coil, due here Friday.
Stay tuned ..
Thanks all !

 

If it was me I'd replace all the coils while you were at it. At this age and mileage they'll probably start failing one by one but I do understand budgeting. Glad you found the problem. As far as your slow to warm up issue the first thing that comes to my mind is a stuck open thermostat. If it keeps happening I'd check the radiator temp with an infrared temp sensor to be sure it is indeed not warming up and not an issue with the gauge.

 

Keep any removed coil(s) in case you need it/them...

 

jbellk75,
I totally agree that all coils are on the way out and should be replaced, I only bought one to see if I was out of the woods ..
I had originally thought it was a more serious internal problem and didn't want to spend money in the wrong direction.
The new coil arrives tomorrow, if that total makes the issue disappear with out question then I will schedule the replacement
of the remaining coils and 8 new plugs.
Good thought on verifying the temp with the thermo/gun (will do)
Thanks for your help ..

 

Success ! purrs like it a kitten I will change the remaining 7 when I do the next oil change
Thanks to all ! this is a fantastic message board ..