engine problem

ok i have an 86 b2000 the truck runs but runs like crap. the engine is in time but cylinders 3 and 4 are dead. like for instance i can drop some water on 1 and 2 and it steams right away but if i do that to 3 and 4 it just sits there and i have been messing with it for over a week and cant figure it out so if any one has any ideas PLEASE HELP. Thanks

Post some engine pics. Had similar problems and traced it to a vacuum leak in intake runners 3 & 4. Not enough to effect 1 & 2 though. Excessively lean fuel mix will not fire even if the plug is firing.

If the engine is in time, have you tried putting the timing light on plug wires 3 & 4 to verify they are firing?

Those plugs are fouled! What brand do you have in there... i hope not autolites?

no i have not put a timing light on 3 or 4 and for the vacuum lines that could be one of the problems cuz i cant figure out how to reroute everything cuz the kid i bought the truck from took off all the canisters and seloniods for the vacuum system and im still running the factory carb, so yea if any one has pictures of the carb with the vacuum lines rerouted please post them

the plugs are brand new and they are bosch spark plugs

Man u r probably screwed.IF some schmuck has tinkered with the pollution crap and removed the wrong thing,u r computer will go to "limp home" mode and that truck will never run right until u hook it all back up OR remove/unhook the computer and replace the stock carb with a Weber or Holley 5200.The stock Nikki is really not a carb but a 1st gen "fuel management "system and there is no way to adjust it to compensate for too much /little vacuum.Sorry.BJ

yea thats what i figured and thanks for the info

I can pull the schematic for the fuel system out of the manual and fax/send it to u if u think that will help.BJ

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