I'm sorry for my first post being a question but here goes...

I've had my XJ8 for 2 months now and put a couple of thousand trouble free miles on it (up to 140k now).

The other day after washing it I drove it home and parked up, came out to it at 10pm to go to tesco and it started with a misfire. drove it off but soon the restricted performance warning came up. Parked it up and left it till morning. Started no trouble, no warnings, drove off and shortly it started again.

it's got a vibration/wobble at idle, and when under load (accel from 50 -70 etc) it has a load rumble and feels really rough plus lack of power.

I left the power off over night and reconnected it, started fine, drove off ok but the misfire has come back shortly after.

It only seems to start missing now when warm. From cold you can drive off smooth as anything with full power, soon as its up to temp it starts acting up again.

Plugged in an ELM obd2 bluetooth adapter, torque reports no errors, no historic errors and no pending errors. ( it displays all the other engine data so i know its working).

HELP! :-(

 

Hey Matthew, I was just getting ready to open a new thread but since you posted this I'll put it here.


My 01 XJR was acting in a similar fashion. Mine ran fine until you got on the throttle hard. I was sure it was a coil pack that was weak and not setting a code. I went so far as to buy a new coil pack and switch it through all 8 with no change.


Having searched the forum some others had found it to be a fuel problem. Well I must tip my hat to the fuel crowd. Changed the fuel filter yesterday and it has almost disappeared. I say almost because if you really wind the motor up I can feel a very small miss. I am suspecting a clogged regulator or injector. I will keep up the research.


My advice, have or DIY, it's not that hard, your fuel filter changed and see if that cures/makes a difference.

My .02

 

Cheers, I will change the fuel filter this weekend as they are only cheap & easy. I'll check the coils this weekend as well once I find that pesky 7mm socket for the covers.

Matt

 

Also clean the throttle body and adjust the throttle cable, they are all in the FAQ section.

 

Finally got round to pulling the plugs out and somebody has fitted cheap BOSCH +8 FR7DC+ spark plugs that cost about £1.50 each... which im guessing wont help

 

I changed them with double platinum autolites because that's all they had at the time. I have since changed them again with the NGK's. I think it runs a little better with the NGK's. Thanks for tip on the throttle body. I used to clean the XJ6's all the time. Need to do it to the XJR as well. Maybe today as it's raining so no pool today.

 

Not changed the plugs yet but i've managed to get an error code out of her, P0301 and P1316 which says misfire on cyl one.

So what order are the V8 cylinder numbers and i'm guessing its replace the coil time? I would swap the coil to another cylinder to test but its really inconstant at producing error codes so I could be waiting ages for it to flag again.