My '91 B2600i 4X4 starts and runs great, but has an intermittant miss that comes and goes. Sometimes it will run fine for 2,3, 5 miles, then stumble and miss on and off for a mile or so, then run fine again. Have replaced coil, wires, cap, rotor, plugs, and fuel pump. It almost acts like a vapor lock kind of a problem, but it doesn't seem to need to warm up much before the problem starts. Driving me nuts (short drive!). Suggestions?

 

I just bought a 93 b2600I and it does almost the same thing that you described. I have replaced same parts as you except for the fuel pump and my coil was good. Still have the same problem. If you find a cure please let me know! I will do the same. Thanks!

 

Have you replaced your ECU?

 

make sure your plug wires aren't touching metal, you might also check for any loose wires, alot of times intermittent problems are caused by a loose connection or a bare spot on a wire grounding out