Hi All,
Just wanted to post a success story here for those of you who are having a dilemma with #5 spark plug fouling, pinging on acceleration, lack of power, oil burning, anti-freeze burning and all other sorts of engine problems. I changed out my upper and more importantly, lower intake manifold gasket and my 1994 Explorer has never run better. It took me about 5 hours to rip it all apart, 2 hours to clean everything up real nice and 4 hours to bolt everything back together.
The truck has never run better. Tons of pick-up and power. No more annoying pinging on the highway either. The only real snag that I ran into was that when I removed the EGR valve manifold tube, it was so rotten that it broke off at the exhaust manifold. It cost about $170 Canadian to buy a new one from Ford. (there's no after-market part for this). I'm now wondering that since it was so rotten if this didn't affect some of my performance problems.
Anyway, just in case anyone had any doubt about trying this themselves, all it takes is a little bit of time and patience to clean all the parts properly. You'll also need valve cover gaskets to do this job as they bolt over the lower intake manifold. I'll be taking the upper intake manifold off sometime next week to gain access to the lower intake manifold bolts to retourque them to specs. I've got a feeling they'll have loosened off a little due to the new gasket. I also plan to retourque them every year or two to ensure they stay snug and don't start leaking on me, a real problem with this vehicle. That's about it. Good luck to anyone who wants to give it a try.