Dodge: stalling problem/98 dodge ram, muffler shop, dodge dealership

Question
We have a 98 Dode Ram 1500 (V-6)w/ only 15,000 miles. Here is the problem, which we cannot get diagnosed. We just want it fixed,as we have 4 years of payments on it! If you just let it run wile sitting in park,it will stall. When driving, at about 40-50 mph,ALL AT ONE TIME THIS HAPPENS: it feels like the engine is cutting out, speedometer jumps down about 10 mph, fuel gauge flucuates a little or all the way to the needle, and the check engine flashes for just a split second. Also, when the overdrive is off, it will actually come and stay in overdrive until you manually change it. And-- when you come to a stop at a red light, it stalls as if you have turned the engine off...have to crank it back up to get going.
We have had it to the Dodge dealership and other shops to be diagnosed, and NO error codes come up, even with the computer testing sytem that runs while the truck is driving. NO CODES AT ALL! The Dodge dealership put a new computer in...didn't fix the problem. We then had the cam sensor and the crank sensor replaced...didn't fix it. The problem actually started after we had the fuel pump replaced and a tune up (new plugs & wires, cap & rotor, throttle body cleaned), so not sure if any of this could have caused it or just a coincidence. We asked another expert on this website, and he said O2 sensor. Changed both of those today (has two), disconnected the battery so the computer would reset. Let the truck sit and run, and in about 3 minutes it completely stalled out. Not fixed!
Now what? What is wrong with our truck?
Please help!


Answer
Vanessa,
How long have you actually had the truck?I know it says 98 model!Also did you buy the truck from a dodge dealership?A catalytic converter could also cause this problem.Mine was hesitating and shutting down until i had the converter changed,But don't buy one from dodge i priced one from Dodge,it was $600.00.I went to a muffler shop they installed one for $175.00.As far as the cutting off sounds fuel related,but on these computerized trucks and cars these days it's hard to pinpoint exactly what the problem is caused by.Let me check just a bit more and i will do another reply to this response.i'll respond back tonight.
Thanks RamMan....I am sending this to another mechanic (friend of mine ).I will let you know more when he responds,This one blew my mind,i would have told you some of the things that you had already changed out!Hang in there,we'll figure it out.I'll do another follow-up