'94 LT1 running rich on left bank, intermittent code 43

[formul8]

Right bank seems fine, left bank is VERY rich. Soot all over the exhaust tip and black cloud whenever I floor it.

It has an intermittent code 43. It will run fine for a while, then struggles at idle and the CEL comes on and then idles fine again.

It has new plugs, wires, Opti, knock sensors.

I'm stumped.

 

[rlg]

codr 43 shows to be the electronic spark control circuit module on my 90 FSM.

 

[toptechx6]

Right bank seems fine, left bank is VERY rich. Soot all over the exhaust tip and black cloud whenever I floor it.

It has an intermittent code 43. It will run fine for a while, then struggles at idle and the CEL comes on and then idles fine again.

It has new plugs, wires, Opti, knock sensors.

I'm stumped.

The two issues may or may not be related, I have had a code 43 in my 93 and it caused no discernible change in the way it ran. I would start with some basics such as checking fuel pressure, also pull the vacuum line off your fuel pressure regulator and inspect it for raw fuel, also do a "sniff" test if you don't actually see fuel. If the regulator diaphragm is bad you should see or smell fuel at the vacuum line. It the pressure is at specification, see how long it takes to bleed off after turning the key off, a quick loss of pressure might indicate a leaking injector, good luck.