Why does my Service engine light turn on and then off consistently?

Thank you for replying so quickly. I have done that and also had a few places check out the problem. Their scanners bring up 15 different codes and they say they have to run a diagnostics check just to figure out what the problem is.

NO, that kinda sounds like FISH-EE! i had a lot of different codes come up on my F-150 a few years ago,and it ONLY turned out to be a vacuum leak..replaced one hose that was sucked flat,cleared the codes,light never came back on!

How were you able to narrow it down to one problem? That is what I can figure out

i got lucky! i cut a piece of foam insulation back(just looking at different things)..i could hear a little vacuum leaking somewhere,so i cut the insulation back about 3 or 4 inches and then i could see and really hear that the PCV hose was sucked flat,split..like i said,i got lucky! i was at a parts store when this happened..i took the old hose off and they gave me a piece of hose from their scrap hose box at no charge.put the hose on,the engine smoothed right out,cleared the 9 codes,the CEL went off and never came back on,still driving it>316,000 miles on 2000 F150 4.6L...