We have a 97 blazer, 4.3 4x4. Just took to the shop cause it was missing real bad. The plug wires was jumping fire even the coil was jumping fire at the base of it. It's a new coil, the old one done the same thing, took it to a shop they put new plugs and I had new wires they put on. The wire came from advanced auto, they are 7mm wires costed 52.00. Wasn't the cheap set. Plugs are NGk plugs he said they use them all the time I'm gm motors. It's a little bit better but stil cuts out and misses real bad. Any thoughts?

 

Any ideas at all?

 

Timing may be off

 

Dizzy cap? Rotor? Use only AC-Delco for those parts, accept no substitutes. Make sure you put dielectric grease on and in the dizzy posts when you attach the plug wires. Also a dab of dielectric grease in the plug boot before sticking them on the plug.

Are the wires tucked in the loom brackets/wire separators? Or are the wire holders/separators missing or broken? If the wires are touching each other, that's a contributing factor.

I'm not a fan of Chinese wires, no matter what the price is. What brand were the wires?

For timing, you need to check the CMP offset (sometimes called CMP retard) with a scan tool. Needs to be over 1000 (maybe 1200) RPM when you check it. The reading from the scan tool must be zero +/- 2°. Adjust at the distributor as necessary. Get it as close to zero as possible.

 

#1 get rid of the NGK plugs & install AC Delco 41-993 plugs.

#2 make sure the wires are installed correctly, (firing order).

#3 post the DTC's in the order they are retrieved.

 

Timing is at -2* cap and button are new. I doubt they put the grease on the plug wires either end. I took it back to the shop that worked on it. He worked at a gm dealer for 15 years. He said he will check it out again.

 

"Timing is at -2*"
If that's ignition timing, there's a problem somewhere. Engine at operating temp, closed loop operation, all accessories off, trans in park or neutral, ignition timing should be ~18 degrees. If your "-2*" is CMP retard, it is within spec.

"cap and button are new."
They really need to be AC Delco, if you are expecting the engine to run well. Yes, it really does make a difference

 

I only used NGK plugs in the first gens and had no issues at all. Now, plugs and wires cap and rotor were all delco

 

Ok changed plugs to ac delco, the cap and rotor are ac delco. Coil came from advanced auto. Still jumping fire from coil wire, 4 plug wires, coul is still jmping fire from tower to the mount on the coil. We had a transmission put in it, that's when it started running bad. We thought maybe distributor was bent so we put in a new one took to a shop and had it timed. Thought bout going with 8mm wires but those are 126.00.

 

Voltage follows the path with the least resistance to ground. It is finding that path before it can reach the spark plug(s). There is high resistance in either the coil, coil wire, cap & rotor, plug wire(s), spark plug(s), or spark plug(s) gap is too wide. Guaranteed that's where the problem is. Without test equipment, the process of elimination will eventually cure the problem