91' 240SX KA24DE running a little rich, enough to build carbon over 200 miles

[Soravia]

Hi I have a KA24DE engine that was swapped over from a wreck and pieced together. The EGR is completely gone and the hoses are plugged according to a write up here on the forum. (aside from big one under the throttle, I think I need it for idle)

The engine runs strong, I can press on the gas and make hard acceleration and it won't miss a beat. (Used to before the vaccume was capped)I have new Platinum4+ plugs, new O2 sensor and plug wires along with new distributor and timing adjusted by an experienced mechanic.

But the car is running a little rich and builds up carbon on the spark-plug over time which causes the plugs to not fire well. I've already replaced the plugs but I suspect the fuel is still rich.

Is there a way I can adjust that? I was thinking of messing with ECU but it seems to cost a lot. Is it a good idea if I let some air bypass the MAF to remedy it? I think the MAF is OK since I can accelerate and idle very well, just that rich fuel is still there to a degree.

Thanks

[180fan]

you can lean out the mix using something like an AFC if you don't want to pony up for an ecu tune. My suggestion though, try some normal NGK coppers and see if that fixes your problem.