Hello,

I have a 2001 S-type and would like some input on a problem I have been having. A couple of months ago I had my jag in the dealer for its 40k service and when they were driving it from the back of the lot to deliver it to me it stopped running. The person tried to restart it and it would crank but would not start. The mechanic came out and checked the fuel pressure and a few fuses before connecting up a lap top to the OBD2 connector. The computer did not have any error codes. It was too late to do anything about it at the time and I left it to be looked at. The next day the found that the coil on plug fuse had blown. When they replaced the fuse the car started but it did not run very well. They called me to suggest that there must be a coil problem even though the computer did not show any error messages. I reluctantly agreed to have the coils changed.
The car did run fine after this service but a couple of months later I was driving down the highway and noticed a skip in the engine as I tried to accelerate up a hill. I eased over the inside lane and kept on driving and it seemed fine when I accelerated on a flat road. As I neared home I turned onto the side street that leads to my street and as I came to a stop at a stop sign the car quit running. The coil fuse had blown. I replaced it with another 10 amp fuse and the car started and seemed to run fine. I drove down the road 30 yards and turned on to my street (which is a sharp incline) and as I attempted to accelerate, the car quit again. The 10 amp fuse had blown again. I replaced it with a 15 amp fuse in an attempt to get the car home (only 200 yards) and it started and made it up the hill with no problem.
After a couple of hours of sitting I replaced the 15 amp fuse with a 10 amp fuse and attempted to reproduce the problem but could not. I drove around for over an hour going up hills and accelerating quickly in an attempt to create a load condition but could not make the fuse blow. I would appear that I have an intermittent condition and would welcome any input possible as to what the source might be.
I don’t think that it is a short because a dead short should have blown the 15 amp fuse also. It appears to be a short lived spike in current draw that is blowing the fuse. I don’t think that it is the coils because they were replaced only 500 miles ago. Any suggestions.

George

 

Thanks for your response. It does call for a 10 amp fuse.

George

 

Thank youfor your advice. It did turn out to be a bad coil pack. Lukily, because the coils were only 2 months old the dealer replaced it for no charge. Thanks again.