I bought a "94 Camri , (4cylinder) that doesn't run. It wasn't getting fire from distributer to plugs so I grounded the yellow wire from distributer cap & finally got it cranked but engine miss fires & seems to have no power. Hoping if I can learn why I had to ground in first place I can figure out what to do next in getting it running right... any suggestions are welcome & appreciated. PLEASE HELP?

Try grounding at another location from a clean place on the engine to the Negative post on the battery. It sounds like you may have a poor engine ground for whatever reason. Both ends of both battery cables need to be clean and tight, free from corrosion. Any redundant ground that were originally on the engine need to be there now. That should take care of the no-start/no-spark issue.
The misfire could be many things: poor fuel, wrong plugs, weak coil, etc. Then again, you may find that problem goes away with a properly grounded engine. Let us know.

Regarding start/spark issue (or lack of) applied fixes suggested that I hadn't already thought of & happy to say that's no longer a problem.
Most problems misfire/performance have also been eliminated by making a check-list of issues similar to my own including those you mention & along with relative ones I found on my own. Happy to say that with your help at least an 85% improvement has been made... not bad for a 1994 model. I still have a few general maintenance issues that need to be addressed. Those I plan to take care of this week. Thanks CaptainRich, for your input. & Many thanks to askmehelpdesk.com for this site