I have a 1994 Chevy s10 truck with a 4.3 liter - vin W. The problem Im having is number 2 cylinder and number 3 cylinder dont seem to be firing properly. Changed plug,wires,cap and rotor. Has spark, and has good compression on both cylinders. When motor is running it sounds like its missing on two cylinders. I can spray water on the exhaust pipe of each of these cylinders and can see the water will not disapate like the other cylinders. Plugs look clean, but dont look like there doing anything. Checked the spark on them by pulling them out and running the motor and the plug is sparking. Not sure what to do next. Not fimilar with fuel system on this truck.

SOURCE: have replaced whole ignition system

Have you taken the passanger side valve cover off while the cars running? Doing this you will see if the valve is opening at the intake valve allowing gas vapors to fill the cylinders so as to ignite and exit out the exhaust. No fuel from intake valve no heat from exhaust. I have another idea as well but this is the quickest and most simple.

SOURCE: 1998 Cavalier No Spark in cylinders 1 & 4

ignition mod. grounds,pcm or timing belt could all be it but, I would have to look at timing first.

SOURCE: 99 Chevy 4.3 2 cylinders don't fire (all cylinders have spark)

Sounds like your computer is fried. Check prices at your local recycling yard or EBAY. Ive seen this happen on other makes and models as well, and its always been the computer...

hope this helps!

SOURCE: I have a 97 chevy tahoe. I changed the spark

the number 6 cylinder is located (if you are looking at it from the front of the car) it is on the left side third cylinder back from the front. you probally have a bad injector that is just dripping fuel into that cylinder.

SOURCE: running rough, spark plugs, distributor cap, rotor

First thing you need to know is which cylinders are missing. Then, don't forget there is an engine beneath the electronics. Do a quick test with a vacuum gauge and do a compression test. Check the distributor shaft for side play. If everything checks out good, then do electronic component testing. have a code check run (many parts stores do this free) and get a chiltons or haynes manual and follow test procedures in there.
I refrain from giving repair suggestions with problems like yours because people keep changing instead of testing parts. When I work on my vehicles or other peoples cars, I do testing to avoid buying expensive parts that most times won't correct the problem. At this point the most I'd suggest is to clean the mass air flow sensor wires with a Q-tip and carb cleaner...that often helps and is free. If you run into a problem with whatever you find, ask and I'll try to help.
good luck

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