I have a question that hopefully someone can point me in the right direction. I purchased a 1991 explorer with just under 80k on the clock this past weekend for my 16 YO daughter to drive. It has a rough idle and doesn't run as smoothly as I would expect. the first thing I did was to replace the plugs and wires. There were standard plugs installed, I replaced them with the platinum plugs. Upon removal, 1 and 6 were fouled with a gooey lump of crap. I took it for the smog check yesterday, it passed, meaning no fault codes. I put in a new Fuel filter this afternoon. The old one was in fact clogged. It seems to be running a little better but still has a rough idle. also I can remove the #1 plug wire and I have no noticable degredation in performance unless the 1 and 5 wires are swapped(I know they share a coil) is it possible that I have a bad winding on my coil pack? I put the compression tester on #1 and I am at about 140lbs cranking the engine. I originally thought it might be a bad exhast valve, now I am thinking it might be a little gummed up. This Vehicle was sitting pretty much for the last year, The woman sold it to me with a bad trans that turned out to be a leaking pan gasket and a tranny that was almost 2 qts low. Also the heads were replaced at 20k on a warranty coolant leak problem. I have a folder that she gave me with maint records showing excessive work in my opinion perhaps contributing to the problem. I appologise for my verbosity in advance.

 

the conditions change when you swap the #1 wire with the #5? If so, then its NOT the coil pack, conditions won't change if it is...sounds almost like a bad wire (hey, you can get a bad one...even new).

 

I changed them on the pack, not the plug. I have gotten a little farther though, I found the PCV valvewas sticking in an open position. I figure it must have caused some oil in the cylinders,hence the goey crap. I replaced it and threw a bottle of injector cleaner in the tank, seems to run a little better. I am going to run it a few hundred to see if it smoothes out.