power loss HELP!!!

i have a 1991 MIGHTY MAX 3.O 4WD, it had sat 4 some time, i changed the plugs wires, rotor ,dist cap, and gas tank. it ran perfect . i started like boggin out in drive but in neutral was idling perfect, so i had a new cat put on. it ran good 4 about 2 weeks and now when im driving and get into and gear beyond second it starts bogging out. i changed the pcv valve and the the gasket on the intake manifold and started it up, it smoked 4 a few minutes from the carb cleaner i had used on it , i let it idle 4 about ten minutes then took it for a ride and its still doing the same thing, any help will be greatfully appreciated thanks.

Haven't been on here in years, but figured I'd let you guys know I found the problem. I dropped my tank and seen what I thought was rust in the tank. I ordered it off line from a place in Oregon an it was spotless so I reache down inside the gas and it ended up being a orange shop rag. When they shipped it to me they had the holes taped off so USPS wouldn't detect the fumes and must of dropped a rag inside. When I got the tank I even inspected the inside. But didn't see it. Removed the rag and that was it haha I was about to blow this mother fucker up I was so pissed how it was bogging.