Hesitation During Acceleration

I have a 2002 Silverado 5.3L with 82,000 miles.

Tonight, and for the last week, it just feels weaker. Especially tonight when I tried to accelerate from a stop. The tranny would hesitate before getting going. At higher speeds, it just didn't feel like I had the horses at my command when I pushed the pedal down.

A week ago, I got in it in the morning and put it in reverse. Nothing happened. I had to put it back into Park and then back to Reverse, and it engaged. That was the first and only time that's happened.

Last summer I had the fluid and filter changed. I upgraded my spark plugs and replaced the air filter. I'm trying to think of any other things that could affect acceleration, but am drawing a blank.

I've thought about spark plug wires. I've got 82,000 miles on this truck and I don't know how old the wires are (2nd owner). I know I need to replace the fuel filter as well. I don't have any concrete to do it on and it's expensive at places like Quick Lube, so I've been putting it off.

I haven't had any lights in my truck come on saying anything about engine problems or low fluid.

Any ideas? Could it just be low tranny fluid even without a warning light coming on? Could it be something more serious? If I have to get it rebuilt or serviced, I'm getting a shift kit installed. These slow shifts can be hell on a transmission over time.

Check the fuel pressure regulator on the fuel rail. Pull the vaccume hose off and check for gas.

sounds like a tranny problem, check the fluid to ensure it's full, a nice red color, and that it doesn't smell burnt.

it sounds like it slipping or you don't have the line pressure you need

usually a code will be set if it's slipping, so i think it's a fluid level or pump problem. pray for low fluid.