Problem found ? Maybe...
Well, MAF has been replaced, another tune-up w/standard plugs has also been done. I've noticed a smoother idle, but no major change in throttle response. I've also noticed a small squeak I dismissed earlier as spark-knock, but I'm sure it's now a sqeak! It sounds like what an older style belt system would sound like when needing some belt dressing, but it seems to be coming from the valvetrain?? Lifters, pushrods...do they sqeal? It only does it on hot days and at normal engine temps. It gets worse as I try to bump timing, Im at 7 degrees now, and I'll get the noise when I pass 2800 rpm through 3500 on a downshift or kickdown, then it clears up after 3500 and idles fine? Any help or pointers?