I wouldn't jump on a replacement yet, either. These things are tough. If it's a "half the time" issue, my guess is either a sensor going wonky, connection to a sensor going wonky, or a vacuum leak. If you have access to a code scanner (wish you were closer, I have a SnapOn MT2500 that'd be perfect, saved my a$$ many times!), check your live data and see if anything's out of range. Also, start the engine and listen to various places and see if you hear a hissing sound (vacuum leak). Most, if not all, of the hoses are still available from Mopar if you have a bad one, or you can just get a roll of right-sized hose from Autostoned or a similar parts house.
The other thought I just had - how long since you replaced the fuel filter?