Hello all, I encountered a strange problem the other day, my truck has no low end power and if trying to accelerate under normal load, it starts shuddering violently. If I put my foot down or even go past 1/2 throttle at 50 mph the hesitation feels like I am driving on a washboard. The truck idles fine and if revved slowly, is fine. Upon startup, it backfires and just barely started, clattering and knocking. The problem has subsided for now but the check engine light is still on. For what it's worth, the problem was persisting, and going down the highway, the check engine light blinked on and off a few times then stayed on after that. Any ideas? Thanks!