Engine Performance problem
1986 Jaguar XJ6 6 cyl Two Wheel Drive Automatic 150000 miles
Hi, I have an 86 Jag in great shape. I had the engine rebuilt when I bought it a year ago (at 132000 miles). Have done all scheduled maint since without problems. About 2 weeks ago I drove to work and car ran fine. Leaving for lunch, the car seemed to struggle. Felt like it needed a tune up but didn't stall or backfire or seem serious. Leaving work at end of day it was noticably worse. Planned on scheduling a tune up and turned around and took the car home.
That weekend I tried to drive the car and it was struggling. Flet like it was about to stall, rough idle and overall ran bad. The way back to my home is up hill and car felt like it was " missing", noticable loss of compression and by the time I got home it backfired, but never stalled. I popped the hood and didn't see anything out of line. Then I noticed my #6 spark plug wire had a " split" in it. About an inch long, it split the insulation all the way and exposed the wire. Never seen this before. I changed the wires and test drove the car. For 30 minutes it drove perfect. I stopped and started it several times and felt I had fixed the problem. One block from my home I stopped at a red light, car idled fine, but when I hit the gas the car stopped like someone flicked a switch. No lights or indication of a problem. Coasted thru intersection and pulled up to curb. Tried to restart and it turned over no prob and idled fine. Dropped it into gear to pull out and died again. Restarted car, tried putting in gear, no problems. Drove the block to my home without issue.
I checked the wire connections to make sure I seated them completely, one felt loose. I had things to do so it wasn't til next day I could look at it again. Took it out for a test drive, ran perfect. Stopped at store and went back to house. 2 blocks from home same scenario. Restarted on second try and finished drive home.
1) what could be the cause of this stall and what's the fix?
2) what could have split the spark plug wire in the first place?
I have asked a couple of sites this question and will gladly make a hefty donation to whoever provides the best assistance. I appreciate your help and look forward to hearing back from you as quickly as possible since this is my main vehicle. Thank you.