The fuel pump driver module is relatively cheap to change, but as a rule caused much more severe problems than what your having. Maybe remove spare tire, crawl around the area and inspect it. As far as having problems with a cylinder after 4 wheeling, or going over a good sized bump, sounds like a corroded, or poor wire connection. The wiring going to the Cops, and injectors go bad, and cause weird problems. You can buy harness sections at all the parts stores, Oreillys, AutoZone. Smoke the motor to find any intake leaks. Your motors running too strong to be having a fuel pump problem, but check the pressure just the same. Standard used to make decent quality electrical, but like all else, some money grubbing company took over. You can bet the CEO of Standard drives a top shelf Mercedes, or Jaguar, and has the dealer only service them. Glad it's running better.
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