GTP don't want to shift into 4th @ WOT

[LiquidFire350]

just picked up a GTP a couple days ago. so far everything seems fine, but the other night i was cruising with my buddy in his TA, he took off down the road, I tried to keep up and at about 101 it starts surging. not like its hitting the rev limiter, more like theres no power, im thinking the fuel filter is slightly clogged up, but what i find kinda confusing is, at about this point i think it should be shifting again and its not.

any ideas

[LiquidFire350]

:bump:

[GTP231]

just picked up a GTP a couple days ago. so far everything seems fine, but the other night i was cruising with my buddy in his TA, he took off down the road, I tried to keep up and at about 101 it starts surging. not like its hitting the rev limiter, more like theres no power, im thinking the fuel filter is slightly clogged up, but what i find kinda confusing is, at about this point i think it should be shifting again and its not.

any ideas

There is a speed limiter in 3rd but that's about 108. Not that I would know from experience;) I'd start with a simple tune up and definetly get it scanned just incase its running lean for some reason. Those engines don't care for lean under boost for too long