I was driving my fathers 350 TBI when it started to have intermentent major roughness while under load. Since the problem was intermentent I thought mabey it was just moisture in the ignition so I let it sit for 2 weeks and put fresh gas in. Now it barely wants to start but will run rough under load all of the time. Sometimes it will backfire with a puff of smoke out the TBI when it does not want to start.

The fuel is spraying in a nice conical shape so I don't thing it is the fuel pump. Starter fluid does not help it start any faster.

I checked each cylinder for spark and it is there although I am not sure how bright the sparks should be? I am also not sure if the spark is happening at the right time.

Vehicle has 180,000 miles with an msd coil, and 6al box. Everything else is still stock.

I am off to the store to get a new cap/rotor, plugs, and ignition module. Any ideas what else it could be? Could my cat be cloging up? Thanks for the help,

Tyler