1994 chey 2500 4x4 it starts at times. Id rock it 2 start I hit the module it startd but fails to start now.

My truck failed to start so I changed the starter the cylenoid then it still failed so I'd rock the truck or jump start then it would start. I then found out trucks have ignation control module but cars have relay switches. But it clicks under the dash and I hit the module with a hard stick it started for a few days then now it won't. I want to know what are the signs of this part going out. Is there an on line mechanic i can chat with or get to on line parts or a map of the engine. How do I do that?1994 chey 2500 4x4 it starts at times. Id rock it 2 start I hit the module it startd but fails to start now.
my answer is try to check it out first on auto repair shop1994 chey 2500 4x4 it starts at times. Id rock it 2 start I hit the module it startd but fails to start now.
my husband had this problem with his ford f-150 it turned out that the new battery was not the correct one.