Check Engine Light / flickering problem on 1995 Dodge Ram Van 2500

I'm working on my uncles 95 b2500 ram van and the check engine light flickers on and off randomly but there are no trouble codes can any please lead me in the right direction.

Asked by for the 1995 Dodge Ram Van 2500
does it run at all or what is the rest of the story
Sorry I left that out. Yes it does run and it doesn't seem to be running rough. I also checked the coils primary and secondary resistance
the answere is if a check engine is flashing it is becouse problem is sever enough to damage catalatic con. still didnt answer me is it black smokingor skipping pinging hesatating missing under load ect