2002 GT was misfiring at Low RPM and replaced all the coil packs because 2 cylinders were bad. Ran great for a few days and now its misfiring again, do you think I have a short somewhere in the wiring that is making the coil packs go bad?
Excessive dwell will cause a COP to burn up. However, this usually presents with smoke from the melting COP.
A "noid" style testing light can help trouble shoot this. Attached the test light across the COP terminal. The light should flash with each power stroke.
If the light is on constantly, this is a problem.
Note, while this could be a short in the wiring between the COP and PCM, the odds don't favor it. The usual cause is a bad coil driver in the PCM.
The only fix is a new PCM. Good luck.
PS, I assume that you have checked for moisture in the spark plug wells. Also assume that the spark plugs themselves are in good condition.
How about the COP boots? If the insulator boots are bad, this could allow spark to leak out. If allowed to continue this will damage the insulator boot. Note, it is possible to buy just replacement boots.
It would also seam to me this could be fuel injectors. Consider an injector cleaning/flow test service such as injectorrx.com. Cheaper than new and once done, the injectors are as good as new.
Once I threw a good set of COPs on my car after the crap Accels, I had to run it hard a few times to clear up the idle. It did run a lot better after that, but I ended up changing the plugs anyway and all was well. I'd recommend some Seafoam, as well as Lucas fuel treatment. Perhaps even clean up your MAF while you're at it.
The wiring back to the first plug is fine, no grounds or shorts and good continuity with everything. Do I need to go back any further than that plug? NOID test is next.