I have a 1988 XJ6 vanden plas edition. I also have a problem I have never seen before. Recently my car began having a rough idle and lack of power. I checked all the fluid levels and they where good. I also changed all the spark plugs with new spark plugs. This did not fix my problem. So pulling each plug while the car was running one at a time I determined that cylinder 6 was not receiving spark. Okay, I cleaned the points in the distributor head and it started working. Now to my problem.

I pull #6 while in park or drive and the engine bogs down, so I know that is receiving spark. But when I through the car into REVERSE cylinder 6 starts missing and it no longer receives spark. Put it in drive and it works fine.

I'm at a loss here. I have no idea what causes this. Transmission and engine should be separate, but I know this is an early electronic control car so my thinking is a problem in wiring, but I don't know. Someone told me it could be a vacuum leak but it runs fine in drive.

Any help at all would be appreciated.

 

Redstang:
You've seemingly stumped at least 29 readers! Gosh, strange problem indeed. If you are smelling a spark issue, I'd rule out every spark-related possibility. Especially, if you haven't done a tune up in many miles, the distributer cap and rotor could be replaced. And I'm inclined to be especially suspicious of the plug wires. There is also the ignition coil... but that gets into some bucks. I have no idea why putting it into reverse should cause it to act up. Are you sure #6 is getting fuel?

Anybody else have some ideas beside my nonsense?

Scott