i blew up a previous engine so i swapped in a PI 4.6 from 2000 with 90k miles on it and i have no low end or mid range power. the truck was in limp mode because i didnt have up stream o2 sensors or the knock sensor plugged in so i did all that last week and no codes have popped up since but theres just no power until 4250. i cant even light the tires up on slush from a dead stop but once it hits the 4250 mark it will spin a bit on dry or go sideways in the rain. i have pacesetter lt's, no cats, 3 inch true duals all the way back into cutouts and then into a DI/DO vortech muffler. i have electric cooling fans, ported heads, canned 93 sct tune, open intake filter mod, 265/75/16 MT's with 3.55ls in the rear. anyone have any insight on why theres no power down low? ive been reading and other people say there powerband starts at 3000 but mine is still a dog at that point. the codes that were up were for the upstream o2's and a p1152 code running too rich. could i just need a tune for the PI engine? also put a new fuel filter on because it would drop rpms for a sec at full throttle. it also seems to pull hard when given 3/4 throttle but when it gets passed 30 i hammer it so it wont down shift and it will just bog and that drives me crazy. any help would be appreciated.

 

https://youtube.com/watch?v=PB3yvHpCGK4 I was able to take a ****ty video of how its acting. p1152 code came up again right before the video. It was full throttle from a dead stop

 

Rented a fuel pressure tester and the junk didn't show anything on it. I replaced the driver side o2 and I got a p1151 code. Thought it was a fuel pump but I had good pressure when I poked a screwdriver In the Schrader valve. Thinking its a coil pack or spark related problem but there's no miss at idle or through the rpm range, just hesitation until 4k

 

the truck is now doing something else where it sounds like it has a 2 step or stutter box on it and it comes and goes while driving. this makes me think its a fuel or spark issue now, maybe even the pcm. ill be accelerating and it will sound like it has a rev limiter and wont let me accelerate. if i give it more gas it down shifts and does the same thing at a different rpm. but it lasts no longer than about 7 seconds and doesnt do it for a while. anyone ever heard of this happening? im still stumped and its below zero so its sort of hard to do any testing.