the wires primarily leak power to the engine through breakdown of the insulation as it gets older. not going to be something that you can measure with a meter

New AC Delco wires. New AC Delco plugs. All coils and ICM from 98 moved onto this car.

Drove it several short drives after replacing plugs wires. Drove this morning for coffee. Wife drove to doctor appointment 3 miles away. No problem noticed.

Now it showed up again as I did a short drive to post office. Idling along and felt slight miss. Engine light came on then went off as engine speed increased. No miss. Then as I got to my stop I felt it and the engine light came on. Left it idling so the light would be on long enough to set the code.

Misfire #6.

you could change the injector then to be sure put it in a different spot and see if the problem follows.

i think if you are going to change the manifold though you should block the coolant paths and get the dorman kit that has the revised egr. also should do the aluminum frame LIM gaskets and aluminum elbows, that should take care of all the deficiencies at once.

https://www.gmforum.com/mechanical-1...2005-a-304071/

Took out #6 injector and #4. Switched them. Neighbor that does lots of mechanical work looked at the #6 as he pulled it out in my garage, and said it was gunked up. He said cleaning it out may make it work okay.

So far lots of short drives and no missing or loping.

I've got Techron injector cleaner in the gas now and I'll change the fuel filter after this tank is partly run out.

As for the plugs with the deposits on the one side of the porcelain, someone said it was from the fuel. Someone else said it may be from oil sucked down the guides during high vacuum. If injector #6 was not spraying a good mist due to crud blocking flow or disturbing the spray pattern, that might explain the buildup on #6 plug of the glassy deposit.

I'm guessing I had both a plug misfiring and an injector not working right and causing a misfire at times.

Fuel I use is mostly Shell and Kroger which is also Shell fuel with the same additive package. Put in occasional fillup at local UDF (7-Eleven type market) that gets fuel from a tank farm which I believe is actually Marathon fuel. Can't imagine where I got defective gas if the gas gunked up injector top end.

Cost: $35 for ACDelco plug wires, $42 for ACDelco iridium plugs - $12 rebate all this year on ACDelco plugs, and I'll owe my neighbor for his expertise on the injector clips and pulling the injectors. Hope I'm all tuned up at <$100.

Open for advice and thanks to everyone for their help.

Glad to hear you may have solved your issue!

Just curious if you did any tests on the injectors, when I did my upper intake, and lower intake, I removed all of my injectors, and used a multimeter set to read Ohms, to test the resistance of each, all may not be exactly what is shown in this link I am going to give you, but they should all be pretty close to one another, if not then I'd try to at least DIY clean them, and then retest them, and if they are still a good bit away from the resistance of the others, then I'd replace it, I found rebuilt injectors to replace some that I had that were bad, I only paid around 50.00 per injector.
https://www.gmforum.com/trouble-shoo...e-test-284313/

Also, here is a video of the way I cleaned my injectors, it is a bit backyard mechanic, and not a great video, but it works way better than running the cleaner through the fuel system.

I did something similar a few years back with an old fuel pump and some tubing. But instead of doing it the way he did, I reversed the injector and back flushed the injector. So much more junk came out into a makeshift coffee filter.