yeah i just PMed 331. My problems were pretty much just like his with same codes. I fixed a blown intake gasket and still having missing issues. Did a compression test and not sure if the guage was malfunctioning but no. 2 showed 120 at first then over course of a week and checking it, it showed sometimes 100, 90, 60. If i did the test immediately after doing a test that showed say 100, it would show 0. Did the oil in the hole as well and comp didnt rise. I will try some things today including a new pcm and see what happens. Might also change the plugs and wires and cap n rotor just to see even though those things are current. If they dont solve the issue at least next time when time to change them i will put the other stuff back on as they arent old. also have on the list to get all grounds checked as well as a leak down test done. I'm going to copy and paste this in a new thread also though cause yes i understand how old threads just dont get the attention any longer codes are 511 and 565 and also got a 111 sytem pass. I do have a tune from 05 autologic software that no one any longer uses One guy who seems to be a pretty smart guru, told me that the lifter preload needs to be set/tested also probably. Theres really no noise though, nothing loud, ticking or anything, no chatter. There is just a slight little sound like a fan sort of but i think that might be the engine as a whole. Is it possible the guy who put my heads and intake on in 05 didnt set it correctly and it run but not run as it should? Would it now 9 yrs later be causing missing and such?