[AceInHole]

I just turned the boost up to 7psi today and took it out for a few quick tests. It was all fine and dandy for a while, then I got a hesitation of sorts. At WOT it'll keep going, but it feels like it's on a rev limiter. Basically I just lose a lot of power. It accelerates slightly, but there's a sudden large drop in power.

What I'm thinking:
1. Spark plugs. I'm using Bosch Platinums at the gap they came in. Was gonna switch plugs but after swapping heads I had trouble starting the car. I ended up trying to revert to the "old" setup, and never went back to the new plugs. Gonna try the NGK Copper plugs tomorrow at a .030 gap.

2. It might be the fuel pump, but I'm doubting that since it used to hesitate every once in a while. If it was a lack of fuel I don't think the power would drop so suddenly, and I don't think the problem is consistent enough to be the fuel pump. I've heard the fuel pump is good for like 10+ psi of boost when not using an FMU....

3. Would the TPS have an affect on it? Tip-in retard maybe?

4. Knock sensor? I'm not really hearing a knock or ping (there is a clicking sound for a small RPM range... thought it might be a noisy injector, but i'll pull the valve cover to see if it's the timing chain...)

Finally: spark plugs:
Denso Iridiums are supposedly the best... but how are the NGK Iridiums? Not as good? Still worth it? Would I just be better off sticking with NGK copper plugs or platinum plugs?

Thanks in advance,
PJ