After searching the interwebs, asking a few friends, and trying almost everything I could think of, I still haven't been able to fix my problem. Here's the rundown:
I've got an 1989 5.0/T-5 w/75k actual miles that sat for 7+ years before I bought it. It briefly smokes upon acceleration AFTER a high RPM deceleration in gear (high vacuum condition) ONLY. No idle smoke, start-up smoke, etc... #1 spark plug is black/wet/nearly fouled after 10 mikes of driving. All other plugs look normal. Car starts, runs, and idles ok with a slight random misfire at times, as you’d expect with a wet/black #1 plug.
Here’s what I've tried so far to remedy the situation:
I've got an 1989 5.0/T-5 w/75k actual miles that sat for 7+ years before I bought it. It briefly smokes upon acceleration AFTER a high RPM deceleration in gear (high vacuum condition) ONLY. No idle smoke, start-up smoke, etc... #1 spark plug is black/wet/nearly fouled after 10 mikes of driving. All other plugs look normal. Car starts, runs, and idles ok with a slight random misfire at times, as you’d expect with a wet/black #1 plug.
Here’s what I've tried so far to remedy the situation:
- Replaced spark plugs
- Compression tested cold/dry 116-124psi across the board
- Disconnected PCV system (no change)
- Replaced PCV, grommet, & screen
- Replaced all valve seals with new Viton seals
- Swapped injectors around & rechecked plugs
- Installed a platinum iridium plug in #1 to limp by for more diagnostics
- Endoscope confirmed crosshatching still present in #1 cyl, no cylinder damage, & no piston damage
- Added Marvel Mystery oil to engine oil
- Added Lucas HD oil stabilizer to engine oil