why is blazer missing on even numbered cylinders?
2000 blazer with 4.3 vortec. Truck had occasional miss while at idle. Slowly became more common. Plugs and wires are relatively new. Had trouble with Distributor cap before and is a common problem with this motor. Decided to swap it. With new dist cap installed it is running on 3-4cylinders. All wires have been double and TRIPLE checked. I'm not new to replacing them and I'm Certain they are on correct. Used a craftsman spark tester that lights up when current passes through a plug wire. It simply rests on the wire for this test. Drivers side cylinders 1-3-5 all firing strong. 2-4 completely dead and 6 showing dim flicker when rpms are increased. Pull plug wires 2-4 to see if it runs worse...no difference so I assume they ARE truly getting no juice. Pull 6 and it runs worse but I get a blue/white spark that arcs across the top of the coil. Any ideas as to what could be wrong?
It sounds like the cross fire fuel injection is acting up. On those Vortec engines, you don't have true sequential injection. All the injectors on one side of the engine fire at the same time, then the other side, all at once. Since all 3 cylinders on the one side are acting up, I would suspect that those 3 injectors are either dirty or malfunctioning.
check the power from the distributor cap side, this problem sound like ignition wires have a high resistance, sometimes the new wires comes defective.
Rafaceb, When I tested the wires for current, this was done on the first 3inches of each plug wire directly from the distributor. I'm wondering if I simply have gotten a bad Distributor cap? The odd part was the spark that jumped across the coil. Any idea what could cause that? A coil is just like a rotor button in the sense that they either work or they don't... right?
Also... Michael, thanks for the suggestion. THe only thing that would have me leaning away from clogged injectors would be the fact that I just had a new spider and all 6 injectors replaced about a year ago. I understand that doesn't make much difference if I pick up some trash in the tank, but I have swapped the fuel filter approx. 10K miles ago thinking she was starved for fuel. Turned out it was the core of the catalytic converter blocking airflow. Removed the cat and she ran like a champ until now.
as Michael also said malfunction ! check with noid.light if possible
it is missing on 3 of 4 silver
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