DOWN ONE

I have a 86 XJ with the 2.8 right now Iam just trying to get it to run decent. It has 137000 miles on it. When idleing it is rough so I pulled plug wires while running to see if itwas running on all cylinders. When I pulled off the wires it got worsea ( which is actually good) All except for when I got to drivers side closest to fire wall, ther was know difference. Which tells me that cylinder is not firing. What can I check to remedy this? I am in the process of searching for a 3.4 for a swap but all I can find is fuel injected 2.8's. Any help would be great. Jcwxj

Easiest would be to swap one plug wire for the bad cylinder. Problem could be plug wires, plugs, distributor cap, or mechanical. Not familiar with your engine, so if it has multiport injection, then you could extend the list to injector, injector wiring, and computer (least likely). Under mechanical, I'd start with a compression check. Very low compression will cause a misfire on the cylinder that's low.

The 2.8 v6 is carburated it is a real dog.But if I can get it to run right for the time being that would be nice.(till a donor motor is found)
jcwxj

Being carburated eases the trouble shooting. If I were you, I'd do a compression check to determine the overall condition of the engine. If it's with in reason--especially the pressure variance between cylinders (highest vs lowest), then I'd change all plug wires and plugs, as well as distributor cap, points & condenser. That should take care of your miss.

I changed distribtor cap and wires.That kept it idling for 5 minutes.After about 3 minutes I got some BLUE SMOKE OF DEATH. Could just be a stuck valve the truck sat for roughly 5 years before i got it and drove it 45 miles to my house.Its a shame the body and mechanically it is in great shape( other than the motor). I think I might just dump it.
jcwxj

There are no points & condenser on an 86 2.8 v6. I would also check that there is no corosion in the distributor cap on that cylinder. Aluminum contacts look fine untill you pull the the wire out of the cap & find corosion. Check the wie with an ohm meter for an open in the wire. Chang the plug with a known good one (take a good one from the next cylinder & see if the miss follows to that cylinder). Inside the cap check the contact where the rotor passes for corosion.

The intake manifold is widely known for sucking in gaskets on these. When it does it on the bottom, oil is sucked in. I would put a fuel injected 2.8L into there in a heartbeat (just needs a balanced flexplate to work) Even without the EFI, the later 2.8L is far better. (wider bearings, stronger rods, better fit gaskets, etc)