was wondering if anyone had similar problems or maybe a solution to my problem... i have a 92 blazer with the 4.3 CPI vortec vin W4x4 auto.when i first start it after its been sitting for a while and cold it runs fine decent power, but it diminishes as the engine gets hot (it doesnt overheat i mean just operating temp), then no power, misses badly cant floor it or it stumbles i really dont know where to start looking for problems so any help is much appreaciated thanks

 

bad catalytic converter possibly, do you get that bad egg smell whenn you try to give it gas?

 

no thats why im puzzled

 

Have you checked plugs, wires, cap & rotor? Not just for new/good, but for where they're routed.

 

I would also tend to say that it may be a bad catalytic converter. You could try removing the oxygen sensor and seeing if it runs properly. I believe that the 1st gen trucks will run without an O2 sensor. It will be loud for sure, but should run and if it runs better, then it means that your catalytic converter is plugging up when heated.

The other possibility is a failing coil pack. I am not quite sure if the early CPI motors have an ignition control module or not, but if it does, it could be that.

 

I go with Kyle on these two. I believe the '92 does have a ICM in the distributor and that would be my first suspicion of trouble, butif there is backfiring along with the engine stumblingthenthe bad coil would be my first guess.

 

well my problem is not much better, today i went to this mechanic because he said he would look at it for free, which he did, i told him the smytoms about missing when at operating temp, so he hooked up a vacuum gauge and it showed good vacuum at idle , he said it had good fuel pressure because it was idiling smooth, and his diagnosis was that the fuel injectors were clogged, so hooked up this cleaner to the PCV hose and ran the cleaner through it, when it was done, he said go drive it and come back, i took it down the street and it ran better, but still has a little bit of a miss on the top end, so went and bought a plenum gasket so i could what was going on under there, i found no leaks, i also bought some fuel injection cleaner, i took off the spider and cleaned it out the best i could thinking it would help, i also took off EGR valve and cleaned it too i cleaned the upper plenum too, well after a couple hours of doing i get it back together and wait for it to warm up, go for a ride and it will hit the rev limiter but only if i dont floor it but ease into it till WOT, i got back to the house and went back to where i go four wheeling, put it in 4LO and tried having some fun, well not really, it is still doggy and runs like the same before i took it to the mechanic, i put it in 4HI and tried doing some donuts and it wont even spin the tires, 2 wheel it barley spins the rear on grass, that is the amount of lack of power it has, this thing is driving me crazy so much i cant even explain it, does anyone have any answers ive tried everyones ideas and nothing, thanks for the help, bt im at the point where i just want to floor it till it blows up