This is a common problem with the 2.4L. This engine uses a "waste spark" ignition system. It fires cylinders 1 and 4 at the same time and 2 and 3 at the same time. What affects one cylinder usually makes a mess in the sister cylinder. The Ignition Control Module (ICM) communicates with the computer and directs the module when to correctly "time" the sparks. On the output side of the ICM, there are three terminals. One is +12V with the ignition on, the other two are battery ground when the ICM pulls them to ground to fire the coil.

In that you’re running on two cylinders, it sounds like it is a coil or coil housing. If the coil is bad, it will affect both 1 and 4 or 2 and 3.

That said – it could also be the electronic fuel injectors – but they typically go bad one at a time, not in pairs.

Word of caution - this ignition system has been known to shock the living bejeebies out of more than one person attempting to perform "live" testing. Be careful - go bathroom before testing - trust me on this!!

Good Luck,
Glenn