Hesitation with 99 Tahoe

[99 Mob Mobile]

My 1999 Tahoe 4x4 5.7 liter with 139,000 miles and it has a hesatation when you gun it from a dead stop or any speed below 10mph really...If I'm on gravel or grass even when i floor it, it will not spinthe tires..somethings obv wrong.. I installed a K&N cold air intake but its been acting up before that and recently in the last 3 weeks its been getting worse and worse..i was told it was highly unlikly that the fuel pump was the problem cause they normally just quit and dont slowly ever so slowly die..i was told either abad fuel filter or water in the gas.. I put a bottle of dry gas in it and that night after the dry gas had been in for several hours she ran fine and had all kinds of power i figured Yes i solved the problem.. then igassed it up 2 days later this time with supreme and the bogging came back worse then ever.. i installed a new fuel filter just last night and it seemed to clear up..then today it started bogging again.. it boggs around 1500-2000 rpms then it will hesitate after for a second.. My buddy drove it today and it didnt bog on him really but it hesitated around 1500-2000 rpms like it always did and he gunned it from a dead stop and it did bog alittle and he said it felt lke it was cutting out on a couple cylinders when you gun it.. but he wasnt sure.. it clears right up after 2000rpms and runs perfectly fine..even if your cruising down the highway at 75mph and floor it to pass someone it passes them perfectly fine..except another thing my buddy notice was if you floor it and when it goes out of second gear when the rpms are right up there and when it goes into second it makes then CRUNK noise in by the motor.. its not the transmisson the first thing he thought of was a loose motor mount but i would think i'd notice it alot if it had a loose motor mount.. I did have a new engine installed 2 months ago though.. so its possible for an engine mount to loosen up..

I have no check engine lights on..i really have no idea whats ailing it.

Any advice would be great..

[asia 1]

Try spraying your MAF and throttle body with MAF cleaner by CRC.