Attn: Wrenchheads, help me diagnose my truck's lack of power.

[Carm]

The fuel filter was my first choice.
Other possiblilities

Fuel injectors dirty - run an injector cleaner. - Should have injectors in most cars after '86
Fuel pump, going bad or not getting enough juice.

Did you gap your plugs or did someone do it for you? Or did they come pre gapped.
Id recommend platinum tip. They last longer then regular plugs.

Also since your truck has such high miles, the catalytic converter might be clogged.

more change :
Carm