need some input on new engine prob PLEASE HELP
 

hey guys, as some of u know i just dropped a new turbocharged engine into my 91 accord coupe, and it has been running good. I got the charge piping in yesterday, and made the dp, and today i replaced the feul pump and started tuning it in my garage. So i take it up to about 3500 rpm and she is running mint and sounding great, but when i hit about 3800-4k it starts studdering a lot, and gets really really rich. This makes me think that a spark plug isnt firing because the a/f ratio up to then was at a constant level, studdering starts, and it richens and feels like i am hitting a rev limiter....and doesnt wanna go any higher. Now my computer is also spitting a 'coolant temp sensor' code, and this is tied into the ignition i believe...i just replaced my wires tonight, and they are fine and not grounding out or anything.....anyone have any kinda ideas about what is going on here to help me out?