I have a 2003 Ram Van, 360 with 97,000 miles. I am the original owner, never had a problem until last week.
When accellerating the engine sputters, backfires, it seems like it is going to stall..feathering the gas pedal will get me up to speed whether it's 35 or 70. The cap, rotor, wires and plugs were replaced at about the 75,000 mile mark for normal maint.. I went ahead and replaced again the cap, rotor and wires...same problem...
The fuel pressure stays at 50 psi, at idle and when accellerating and the sputtering exists.
Checking the codes through the obdII always gives me random cylinder misfire with random cylinders...ie, 2, 3, 4, 8.
I have also ran through three full tanks of 93 octane and added fuel injector cleaner, none the better.
I normally drive the van about 100 miles per day for work and this sputtering is killing me.
If anyone can advise in the direction of where to look next, I would be grateful.

 

Assuming you've checked for vacuum leaks and found none. I would first replace the crankshaft position sensor. If that doesn't do it, replace the cam sensor in the distributor.