SR20det running need serious tech help.

[burnsauto]

RS is an easier route, but it may not solve your issue. I'd hate to see you sink 4-500 bucks into an ecu to find out that it's not going to solve your issue. There are cheap(ish) stand alone ecu's that can also help diagnose an issue through live data collection (like megasquirt), while also getting the car running the way it should after your mods.

The way you describe the problem in your original post doesn't lead me to think it's just the tune though. If it were a constant problem from the moment you start it to the moment you shut the engine off, sure...tune for sure. But it sounds like its a much more intermittent issue.

My advice, if you want any, is to get a friend with an SR. (if you don't have one, get one.) If said friends car runs well, spend an afternoon swapping parts related to the ignition system, and see how that changes things. I'd even change that temp sensor, just to be safe. It make take some time to slowly go through everything, but its better than throwing money at it without knowing the exact cause first. It doesn't sound like a boost leak, and unless the problem only happens when you start leaning on the fuel system (like when it's only hitting boost), it doesn't sound like a fuel pump voltage issue either. Running an engine with a bad MAF is pretty apparent right when you start it. And as you've described the problem is relevant to engine temperature. My thought process keeps going back either the ignition system, coolant temp sensor, a weak/bad ground, or a bad ECU that starts screwing up once the signal from the coolant temp sensor starts giving a certain reading (like when the engine warms up). Don't change things all at once, go little by little, changing out parts in phases, to pinpoint the actual problem.

Your plugs do indicate a leaner mixture, but not one that's super alarming. The ceramic around the electrode isn't browned, and the ground seems to have even coloring (that's a bit harder to see in your pics). The photos you got in response from Kingtal0n show an engine that's been tuned on the slightly rich side of the spectrum, which any reliable tune should be in. Sure, you'll make more power leaning it out, but power that's on borrowed time.