I am new to Jag and new to this forum and I come seeking advice from those who may know something. This is my first British car, I have a 2016 m3 and a beloved 2004 honda S2000 and I do all the work on that car myself.

i came by this car from a relative and it was a good deal for us both...it will not cooperate with me!!

1999 jag xk8 convertible that has sat allot with a dead battery, 39,000 one owner garaged. It was running when I got it and there were no check engine lights...one came on....so i took it to a local british car expert....

he says a have now a ramdom misfire code (number of code to follow when I get it next week)...and there was a lean code...he replaced the mass airflow meter or sensor, that code went away, then the plugs which were original and need of repair...then the ramdom misfire code came on.....

he has swaped out coil packs, mine are good, he has checked each injector, replaced fuel filter....car runs "perfectly" reset light, drive it 45 min and check engine light says random misfire on all cyls. He has given up....
So car will not pass smog....check engine light is on...it's been driven hundreds of miles....

How to I fix this and how can it pass smog with a check engine light on , on a car which he says is running perfectly...

remember, car has sat for a long time, battery is fine i think as it starts right every time even with the lights on. car passed smog two years ago.
former owner never fixed anything unless the car broke down, so it has had minimal maintenance.....coolant is a mess, oil is black, i will change those things.

redid the interior mirror, car is perfect other than the parking lot dents, nice car. Any help will be appreciated...I live in sf bay area, the penninsula, san mateo/redwood city area.

Thanks

 

Those more knowledgable will elaborate but my first thought is to fully check the battery. The fact it starts the car is not proof it is good enough for one of these cars. Search out battery issues here and you will see how important the battery condition is.

 

I agree with Baxtor on the battery issue, Change out for new battery and we need those codes. That is the most important. Owning one of these cars, you will always need to have your code reader in the car at all times. Go out and purchase one and read us the codes..

 

Do not know if you have it over there but if you wish to pass the emissions test get yourself a Terraclean.

In the UK we have our emissions tested once a year and they are quite strict on it. According to the last test the car had it has 0 emissions. I put it down to the Terraclean.

 

Any other codes? These are important clues.

Remove and open up your ECU (with battery disconnected) and inspect it for moisture, corrosion or brown spots, all of which are signs of electrolytic capacitor failure and need for an ECU rebuild.

Also have the chain tensioners been upgraded?

 

wow, only 39,000 miles? That is incredible. I have a 98 XJR with only 53,000 miles. WhiteXKR is correct about making sure the tensioners have been updated even though you/we have low millage.

 

Frankc, here in California you can't get a smog inspection if the check engine light is on.

 

Thank you all both for the ideas
I bought a scan tool it reads my BMW and my Honda but cannot complete the scan with the jag
The garage it's at now will supply the codes and I will post them
The tech also found a Cpu and swaped it out. To no avail

I suspect the battery myself as it would not respond to a trickle charge
The trickle charger charges my Honda battery just fine so it works
Although the jag has a larger battery
Thanks again