Have you driven it since you replaced #6 sparkplug? Is it still throwing a CEL?

With the proximity of the #6 plug wire to the exhaust manifold, my bet is you melted the insulation on the wire and it is shorting out. Inspect that wire in particular, but look at the other wires as well.

sawpped the plug for a new one.used a different plug wire also. no change.I am guessing bad coil pack. young man at AZ said it was possible for half a coil to go bad. what is the icm and what does it do? how can I test the coil myself? If I need a new coil, will the hotter coils be worth the money for better MPG and performance?

Here is how you test the coil...
https://www.gmforum.com/trouble-shoo...-wires-278818/

Stay with the stock coils. Anything else is junk. Even your name brand MSD.

Its weird though, with our coil packs, if it goes bad, then you should see a misfire on both the cylinders its connected to. That'* because that coil pack fires both electrodes at the same time.

that was my first ? to the young man at autozone after his scan, whyjust one cylinder not working? he said it is possible for half of the coil to stop and the other half to keep working. no melted wires. buying multi-meter tomorrow. changed the oil to check for coolant, thet was a negetive. change all coils while I'm at ?

U shld check your #6 injector and if thts fine a smoke test might reveal an injector ring seal is bad ...i had this exact same problem.....

I am pretty sure that the coil can not go half bad. It either works or it doesn't on both cylinders as it is a waste spark ignition system, using both plug wires and plugs to complete the entire circuit.

my new multi-meter revealed a bad coil!! not half a coil, but the whole coil!lol thanks everyone! thanks Mike and Dan! great site!great information! Dan said all coils should be close in Ohms readings. will new coil be higher in ohms than old ones?

They should all be pretty close to each other.

newer the coil lower the resistance