Odd tuning problem.. HELP!

[Chris81]

Alright guys, I need some help on this one..

Im autotuning a buddy's car and it has had a bad hesitation from the time that they did the heads/cam swap, it also backfires at idle a good bit and some driving as well. We got the car to about 50% throttle and it wouldn't act like it wanted to run at all giving it some load.

No misfires, I checked each cylinder and total misfires.
No KR or audible detonation
I'm autotuning and the BENs are pretty close, its not too lean/rich.. so the car is in OLSD.

I'm leaning towards something in the plug wires, but they were replaced.. although they are cheap ones, I think he's going to get a set of MSD wires.

We just pulled one plug and it didn't look bad at all, they are TR6's at about .036.

What else can we check? Coils? Crank and Cam sensors?

Has anyone had this problem before?

For reference, the car is an 01 Formula A4 with a TSP 233/239 cam and PRC CNC LS6 heads, with the usual bolt on's

[Doc]

Have you checked Fuel Pressure?

[Chris81]

No, not yet. I forgot to mention it has stock injectors as well (unfortunately).

Wouldn't it lean out if the fuel pressure wasn't in line? It feels like its WAY fat but the logs say otherwise.