Chrysler 2.4 ping?

Check to see if your EGR valve is operating properly and the EGR passages are open and not full of carbon.

i would guess its got to due with your spark timing or a defect somewhere in that area.

Plugged up EGR passages or a failed EGR valve would be my first guess. Excessive combustion chamber temperatures will cause this problem. Check your ignition timing and check for vacuum leaks first..might be a cracked/broken vacuum line if you're having a lucky day.....

Chris

The modern era 2,4 is a DIS ignition system:

I would say look at the EGR valve for sticking or improper computer control of it.

Also, there is a chance you have a vacuum leak, or low fuel pressure/volume.

Could also be a knock sensor. If you could have someone plug in a scan tool, you will be able to get further info. Since it is a 2000 it most likely has the ODBII system.

-KM

Possible, but not likely on an engine such as the 2.4 where the engine timing is computer controlled. Much more likely candidates are inadequate EGR flow due to clogging (as mentioned by a previous poster), or carbon build-up in the combustion chamber, or hot-spots and/or carbon buildup on worn-out spark plugs (the OP said its overdue for a plug change).