Could be few things. when was last time you did tune up? Try a complete tune up if you do work yourself shouldn't be more than $50-60 and its fairly easy just common sense type stuff so don't need to be too mechanically enclined. If that dont work it could be air fuel ratio maybe too much fuel/air per fuel/air or a wiring etc etc start simple if tight on money start with distributor cap, wires&plugs. eliminating one troubleshoot at time. hope this helps, best of luck to ya!!

I would first start by changing the fuel filter. When the fuel filter is restricted it will cause the fuel pump to work harder and could burn up the pump.

What's it missing, I don't get it.

mine did the same thing maybe ur fuel pump or ur fuel filter plugging up is going out or the fuel injector going bad

My blazer is acting up again. .. about 3-4 months ago it started to miss or run rough when i got to about 50-60MPH but if i speed up or slow down its fine. It also would sputter a little when i accelerate from a stop unless i baby the throttle . It never stalled but Eventually it melted the cylinder 6 spark plug boot. I replaced the plugs and wires and it ran fine up until now. .. its acting up again and i know there has to be something else. causing this but i just dont know what it is. Is this enough info to diagnose the problem? If so, please help me!! I want to try to get it running right by Monday. It runs now but its only a matter of time before it fouls the plug or burns up the boot again. Any input will be greatly appreciated, Thanks in advance.