I HAD THE EXACT SAME PROBLEM! Changed coil packs and plugs and cleaned mafs.. Still nothing. Done a comp test and it was 80psi! Put in a scope and seen bad valves so I got all new ones. When the head was removed I descovered I has multiple cracks in my head. (explanes why it runs fine when cold) its bc the cracks were small but as it heated up the cracks would expand and I would lose more compression. Please take my advice and get a test ran to save u more time.