Hello, i'm sorry for your troubles with the truck! The oil pressure gauge could be showing you an internal engine oil pressure issue, or it could be showing you that the engine speed is dropping so low that the oil pressure is becoming low as a result. I would suspect that this is the case; low oil pressure at base idle on this engine would not cause a stall. In any case, you are likely looking at a conventional "driveability" issue with engine performance. You referenced servicing the plugs, cap and rotor, fuel filter and pump, but you didn't mention anything about the air that comes into the engine. Sometimes, so much air gets into the engine without being checked that it can overwhelm the fuel and spark and cause the engine to want to stall. Check your air box with the air filter, the air tube to the throttle body, the idle control valve, and check for any vacuum leaks at the intake manifold. I suspect this is the source of your issue. I also suggest consulting the help of a local qualified technician - this link will show you some folks near you that can help. Good luck! http://repairpal.com/dodge-within-10-miles-of-floresville-texas-78114
I do have a hole on the driver side of the exhaust manifold in the front there was a bolt above the hole but broken off so I welded a screw there to prevent and more exhaust pushed out and my truck was still acting up could be a vacuum leak