1995 chevy suburban no spark

[DIESELDAN]

My plow truck is a 1995 3/4 ton suburban with a 454. It sits much of the year but usually starts right up and runs good. Lately it has been intermintently not starting. Sometimes it will start and run, other times it will just turn over and not even pop. When this happens I can smell gas so I think its getting fuel.When it does start it seems like it doesn't have as much power and sometimes if I accerlate a little harder it will stumble and kind of backfire, it also seems to be running rich. I was just wondering what are my best steps on finding the problem? Could it possibly be getting too much fuel? I'm pretty mechanical so I like to fix things myself, but those of you who are mechanics have much more insight on electrical problems and what steps to take to find them than I do. Thanx for any advice.

DieselDan

[Jeremy airjer W]

I'd check to see how much spark the coil is able to put out.

Maybe check the cap and rotor for corrosion.

Check the spark plug gap to see if they are worn out.