2002 Dodge 1500 help!

[SteveMcqueenRules]

this may be OT or whatever but. my dads truck throws on the check engine light but when it is scanned it shows no codes. It is driving pretty crappy and he says it sounds like its missing or something. its got me stumped why the CEL would come on but not have a code show up on the scanner.
its a 2002 Dodge (Ram?) 1500 4x4 truck with the 4.7L V8
if anyone has some suggestions on what to do next I would appreciate it.

[Vince@Meanstreets]

It is either something that is failing then correction itself or an intermittent electrical problem that erases the memory and code. Next time try to see how many trips or key cycles you have during the scan. You may have to bring it intro the dealer for a trip with a data recorder.

Note,some 4.7L have problems with valve seats leaking or falling out of the heads.

[SteveMcqueenRules]

thanks for the help. I kinda figured the next step would be to take it to the dealer who would have a better scanner. my dad replaced the front left drive shaft we test drove it and the CEL was blinking i thought it was weird so i look it up in the owners guide in the glove box and it says the cat is messed up and prepare for loss of power and what not.
I cant believe my dad didnt bother to look in the manual before. so now the mystery is solved (hopefully) it should be getting a new cat and exhaust since the muffler was leaking and the exhaust is all crusty.

is there three cats on these trucks or one and two resonators?the crappy repair manual doesn't say.