My 1992 Ford Econoline E-150 feels like it is missing. Jerking off and on.

What is your question?

I just bought this van and it ran fine for a Very short time. Now it keeps jerking jumping like it is missing spark or wants to stall, but it never stalls Ferels like I am going down a bumpy road in a way. It is very annoying and I am worried it will just get worse. Any easy fixes or is this something major? My engine light pops on and off, but never stays on for more than a minute or so. Also my airbag light flashes on and off. To top it off, the factory installed alarm will go off by itself with no "outside" help.