Im not sure if this is the right group..? s-15 Jimmy ,2.8 li v6 , 5 speed ,4x4.
Yesterday it ran fine for 1/2 mi. Then it lost power for around a mile. Finally It wouldnt go over 15 mph. It has a hot spark and good fuel pressure. Whats next? The Cat/muffler?
Having good spark at idle doesn't necessisarily mean good spart at speed. Check your plugs and see what they are telling you. You don't say what year you have, the but 2.8L V-6 dates back quite a few years. I've been in a diesel for quite a few years now, but I think looking at the ignition module/coil, distributor cap and rotor, and plug wires is called for next. Of course you could also have a failing fuel pump. I don't think a plugged exhaust, cat or intake would cause such a drastic change in drivability - more likely a steady decrease in power over time.
Cheers - Jonathan
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