photo 1516 is cyl #3
photo 1517 is cyl #5
photo 1518 is cyl #7
photo 1519 is cyl #2
photo 1520 is cyl #4
photo 1521 is cyl# 6
photo 1522 is cyl #8
Yeah it looks bad.
I see one spark plug looks Bridged fouled shorted out. Had to be running real bad.
Plugs will never cleanup right.
Need a new set.
What spark plugs are they ?
RCYJ12'S Champion?
They are Ok..have used Champions. They don't like being fouled out.
They work good for Racing Champions one the tune is correct hit real clean and smooth under load with correct AFR dialed in.
Autolite equivalent works better for Rough tuning in for me or ACCEL Copper core.
NGK spark plugs excellent too, favorite of drag racers with a huge array of heat ranges ultra cold for high boost or hot heat range for street driving duty what your doing.
Application specific again.
How was the ignition spark test?
A-ok bright blue hot spark ?
Appears white in bright daylight often
Bright blue at night or lights off in garage.
Bad tune yet...
Bad knock sensor..recall that happened to Marc One time on his 1982 Crossfire Vette.
He had a hard time finding the right one.
Another possibility is the fuel pressure regulator failed.
Hole in FP diagrhram.
It the highly polished tool steel seat is scored bypasses leaking fuel.
Aftermarket made in china.
Rough machined.
Polish with 600 grit sandpaper taped to a piece of glass.
Then go 1000 grit.
Then 2000 grit.
Will be 1-2 microns or RA smooth shine like a mirror.
Hardened seat built into center of Fuel pressure diaphragm.
Had to do the same on my 87 Corvette TPI years back.
China supplied. NOS GM Part long gone.
They hate us in the USA.