That would be it. Chasing down a misfire on cylinder 4.
The cylinder power test or whatever at Ford confirmed the hand scanner at AutoZone - misfire on 4 and it picked up an intermittent on 3. They were baffled and wanted $650 to pull the surge tank/intake and "check out the COPs". Pfft. NOT.
I had purchased 4 of the $25 new coils on ebay last year and put those in. I didn't bother with the plugs because I thought the person who welded the cams replaced them (I saw the guy from the parts store deliver them that morning, anyway). Not sure if he did or not, the plugs didn't look that bad but were gapped at ~.050. I guess it never pays to assume that somebody did their job correctly...
Anyway I bought 2 more coils from RockAuto and Autolite XP Iridium plugs and replaced all 8 plugs (gapped correctly at .044 this time) and the coils on cylinders 3 & 4. The car feels stronger but the idle is still wonky, it likes to idle about 650 rpm or a little less when warm, and it feels like a car with a lopey cam. Probably a vacuum leak or something. In any case I should have somebody who really knows Gen 3 SHO motors have a good look at it sometime. As soon as I find one around here, that is.
I might just have to suck it up and buy new coils for the front bank, too, even though I've never had a code for cylinders 5-8. $300 + shipping. Ack. I hope I have a good tax refund this year.
The garage wasn't heated but my little ceramic heater did it's best to keep the temp about 55 degrees - plenty warm to work in.
