After my car all of the sudden started running poorly and the CEL came on I looked it up on the forum and figured out that it was most likey the coil. Had it read (OBD11 port) by an autostore for free and it said misfire on cylinder 4.
Picked up a coil and chaged it. Runs great! Had to guess at th cylinder numbering but guessed right. (v8).

Just thought I send a thanks to all those people that posted on this site regarding this. Saved me $400 bucks! What a resource!

BTW cylinders are numbered from passenger side starting at the rad (#1) and working back and around.

Thanks guys!