87 running lean?

[jesdude7789]

My truck has lost power somewhere and its been a while since i tried to find out whats wrong. It doesnt have any check engine codes but lacks acceleration and responsiveness to the gas pedal. When I push on the pedal at any speed it sounds like the engine revs a little higher than its supposed to and especially if i let off the pedal after cruising at say 20 or 30 mph you can tell that it drops off too many RPMS. I would think its from a vacuum leak somewhere but i've already replaced the intake gaskets a year ago. i rechecked them about a month ago and still good. I also checked the little vacuum lines to the the TBI on both of their ends and they seem fine also. The MAP, IAC, and TPS are all less than a year old and check out fine also. I have been able to watch my live data via my laptop and interface cable. The single wire o2 stays lean at idle and then starts cycling once i rev it a little. then leans again. I don't think it cycles as fast or high and low as it should though. Seems to stay in the middle voltages like .3 to .7 not down to .1 and up to .8 or .9 like i've been told it should. The exhaust sounds kinda cruddy on acceleration which is how i KNOW something has to be wrong. I've had the catalytic converter checked, its good. No holes or anything in the exhaust. The engine has 67,000 original miles on it and has good compression across the board. Could the torque converter not be transferring as much power to the transmission or something like that? Could the AIR PUMP hoses and check valves be contributing? Bad injectors? the fuel pressure is 13 psi. Oh and the entire ignition system is recently replaced as well including the whole distributor. the EGR too. It is really bothering me when it looks like a good truck but it doesnt FEEL like one like it did three years ago. What the heck am I missing?