My 96 5.2 only has 44,000 miles on it. I got a stumble off idle with it as well. Used air valves didn't help. I finally sprung for a new valve and the problem went away. It was the best money I've spent in a while. It wasn't an original Mopar part (would you really still expect to find real Mopar parts?), so I may have to change it before it gets 25+ years old, but I'm OK with that.
After the new valve fixed the problem, I took a really good look at my original valve. I could see a difference in the color of the aluminum around the plunger in one area. I suspect the aluminum has worn away over time, because miles sure wasn't the cause.
Of course I'm assuming you have replaced the spark plugs, cap, rotor and ignition wires... Gene
I think Delphi was the manufacturer for Dodge. They are available from rock auto. The 12 buck chinese ones though you may as well just flush your money down the toilet and save yourself the trouble.
