84 D150 225 with weak spark

Trying to figure out why im getting a weak spark. I replaced the coil and also checked out the complete ignition. If I pull the coil wire and groung it out I get a bluish-organge spark. It will also die out after I drive it a while and then it is hard to start. All this happened after I stopped one morning at the store and come back out and it would not start without having to pour gas down the carb. It started fine before I left home. Also, looking in the Haynes manual they show the #1 piston in front but for some reason mine #1 plug is in the back. Could some one got the dist 180 out? Had this truck for about a year with no problems. Thanks for any help with this problem.

Go back over ignition, take a good look at points/condensor, cap/rotor, and I cannot recall if yours has a resistor block on the firewall or not, ceramic block about and inch square and 3 or 4 inches long mounted to the firewall. been awhile since I messed with that model. check all grounds very good.