Okay so I know there is a million post on this but I have not found anything specific to all the issues I am having. I just bought this 03 g35 coupe 6 speed, it's my first time owning one and don't know much but have been doing a ton of research. I bought it as a drift car, it was only $2,000 but the front end had some damage. Since I bought it I have done ngk plugs gap at .44, replaced coil packs and checked for correct location of plugs, changed ignition condenser, both cam and crank sensor, cleaned and checked all grounds, visual check and throttle body cleaner to check for vacuum leaks, cleaned maf, replaced pcv valve and hose, cleaned throttle body and replaced gasket, new battery. I haven't been driving the car around just because it has a fixed seat without harnesses or seat belt for now, but I'm only getting a p0300 code and p1564 which i think is irrelevant. I tried to do all the relearn process over and over with a stopwatch and nothing is working, also tried unplugging battery for 10 minutes and trying again. It idling extremely low at like 2 to 300 rpm, it revs slow and when it falls it almost dies and sometimes does die. The car was cheap and I've already dumped a bunch of money so I'm trying to avoid the mechanic shop. Tonight I'll be doing a compression test to seal my fate. The car has a full 1320 headers and straight pipe exhaust which I think the flex pipes are leaking but it's after the 02 sensor. Only thing I found odd was after replacing spark plugs I pulled them back out after running the car a couple of times at idle and just driving around the neighborhood and the tips of the spark plugs seem to have some white discoloration which I'm assuming is too lean which makes me think maybe something fuel related, injectors or fuel pump. What's weird is this car starts up perfectly fine no issues and if I clear the codes it actually runs very well for a few minutes then goes back to misfiring what they're really low idle and almost dying on Rev. Any help would be amazing.