As confusing as this may be here's the deal. I had a bad lower intake gasket plus an exhaust leak. This caused my engine to run rich. After I fixed the aformentoned issue with the intake one of the injector pintles came loose from the cylinder 3 injector. I ignored it, placed the pintle in the injector bung and just inserted the injector directly into the pintle and tighten the 4 injector rail nuts down. Heard a noise that I suspect was a vacuum leak and also had a lean condition on Bank 1 and later determined it was the pintle cap not contacting the injector. I glued it back together and the vacuum leak went away and the engine operated much smoother.
All in the midst of this I apparently got some counterfeit Autolite AP606 spark plug form a local parts store.
Engine started running rough at idle again so I decided to pull the plugs and see what was going on. The front bank of cylinders had melted electrodes and and I also noticed all the spark plugs had blued prongs on them. Luckily I had some Bosch R6 Platinums lying around for another project that I cancelled and put those in. Engine runs much smoother now.
Here's my question: Are the melted prongs a product of the lean condition, the plugs being counterfeit or is it both?
Thanks for your input on advance.