o.k been doing some logging, had the tune pretty dailed, no KR and a/f was O.K decited to do a quick run at 9psi, Well it when O.K but the engine sounded a little wierd afterwerd, but no codes. swaped my MAF with my wifes MAF off her truck, (with out her knowing) and when and did another run. My MAF was only showing 27lbs of air moving. I wanded to check it.
I went for another ride and the truck woulnt not go over 4,500rpm and would get a miss fire code. I'd let it Idle down, clear the code and it would run O.K then try it again, with no luck. Pulled the plugs and everything looked O.K. what else could cause it to not go above 4500?
BTW with the new MAF I was seeing 42lbs at 4500.

The 6.0 is bone stock with 20,000 miles on it, I did install 918 springs, but did not change the push tubes because I didn't change the stock cam. Could this be the problem????