[5150Watts]

Here is the problem. My 97 k1500 5.0L feels sluggish. 154000miles. Has the feeling of almost towing something under normal acceleration. If I stomp on it, it will downshift and go no problem, but normal situations is when I seem to have the issue. Have changed plugs, wires, rotor, cap, pcv valve, fuel filter, and had fuel system professional flushed (extra 40miles to the tank now). It does have a harsh 1-2 2-3 shift sometimes but the tranny shop found no damage and says it looks fine. Went ahead and serviced that anyway. Still feels kinda gutless. Does not appear to leak anything. Do lose about 2/3rds quart oil every 3 months. Coolant seems a little bit lower then I remember, not much though. Also, it does have a 4" suppension lift with 33x12.5's but, did not have this kind of power loss until recently. So, any suggestions?