My 1987 XJ6 SIII would die randomly at stops, had a rough idle and stumbled on acceleration. Drove me crazy. I had to do the typical, shift to neutral and coast to stops, left foot brake, right foot holding at 9,000 to 11,000 rpms.

Finally got tired of it, researched what would cause the problem and narrowed it down to the EGR valve. Not the electronc aspect of the EGR system, but the valve itself. I watched a videoo on youtube on how to check the valve, and mine definetly needed replacement.

I put the new valve on (they are external for those who don't know), drove as if I were driving to work, 22 miles one way, and TA-DAH! it ran beautiful. No stalls, no stumbles, no rough idle....and no need for my left foot.

The EGR valve works by vacuum and is located behind the carburator on the intake manifold and looks like a metal mushroom that measures about 3.5 inches across.

1) Take the air cleaner off, disconnect the tiny vacuum hose on the top of the EGR, take a box end wrench, mines half inch, and take off the two nuts that hold it on.

2) Once removed, push the internal disc (you'll see) all the way up towards the vac hose connection and hold it.

3) Plug the hose connection with your finger and let the disc go. If it returns to the original position, you have a bad EGR valve because it's not holding vacuum.

Yours is a V8 conversion, right?


Cheers
DD

Yes, mine is a conversion to an 85 Chevy 305 / V8. I've no knowledge of the Jaguar vacuum system, but since the GM conversion vacuum system is extremely close (so I've heard) I assume the two systems must be similar.

The Jag engine, as used in your model, didn't have an EGR valve at all. Threw me for a loop until it dawned on me that you had a V8 !


Cheers
DD