1996 Blazer has had an engine miss lately while going down the road. The miss starts at about 2000 rpm and goes away when I accelerate but as soon as I go to cruising speed it starts missing again.

I replaced plugs and wires, cap and rotor and it still misfired. Next thing I tried is unplugging the mass air flow sensor and the misfire went away! So I bought a new MAF sensor and installed it and the engine miss is back.

Only code I've received is P0300 one time. Anyone have any thoughts?

 

One of the plugs is misfiring, could be a loose plug(happened to me) arcing wire, cheap cap. Check under hood at night in the dark, (unhook underhood light) look for arc sparks on 1 of the wires or around plug. Look hard can be tough to spot sometimes

 

If one of the plugs are misfiring why does it run fine with the mass air flow sensor disconnected?

 

Dont know, but an 0300 is a misfire. And checking is free

 

Just a follow up but I ended up replacing the computer as the miss is gone!