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cause of #5 misfire 99 blazer?
I'm trying to fix my sisters blazer, 99 4.3 V6 auto. she says the CEL has been on for about a year and the mechanics that shes taken it to all say her catalytic converters are plugged. its also a california emissions vehicle. When I plugged my scanner into it, it comes back with a #5 misfire and thats the only code. I'm assuming that if the cats are plugged, it is because she drove it so long with the misfire. I'm not really sure where to start or what to check... not used to working on vehicles with spark plugs lol.
changed plugs and wires, every plug is getting spark. still getting misfire codes, sometimes random misfire, sometimes #5 and sometimes #6. its an electronic ignition, no distributer cap.
1 Answer
- 1 decade agoFavorite Answer
Just change the spark plugs. To test and make sure the distributor and wires are good, do this; Take one plug boot off, put a flat screwdriver near the end of it, and have someone crank the engine for a sec. You're looking for a spark to jump from the wire to the screwdriver. That indicates you're getting spark to the plugs. Now if they, Particularly #5, are not getting spark, check the wires for cracks or rusty contacts. And take the distributor cap off, see if it's in good shape. All these things are relatively cheap and easy to replace, so don't sweat it too much. The cat is expensive and I would try to get away with not changing it, but you'll know soon if it really is plugged.
