Here's a couple of things I've encountered with my 20v, they might be worth checking on yours, since I had similar issues to you.

Knock sensor (someone had screwed in a random knock sensor on my block, if this is the case, you will get an engine check light)
Fuel Pressure Regulator (mine was stuffed, did not hold the correct pressure in the rail)
Fuel Injectors (2 out of 4 were dead, had to get them flow tested, and replaced)
VVT pulley (mine was defective, and needed replacing)

Fuel Injectors are really easy to miss, as you can't get a diagnosis from the ecu. I've been fooled twice on two seperate engines looking for the root cause elsewhere.