car won't stay running

I have a 98 stratus 2.4 L that will not stay running.I start the car and it runs for 10 to 20 miles then starts to miss and will not rev. I can put the car in Neutra sut the key off and ti will run fine for another mile or 2. I have changed the cam timimg sensor because it coded. The coil pack was tested at room temp and was good. I changed the feul filter and checked the cat converter. The only other code is for insufficent egr. HELP THIS THING HAS ME STUMPED.

possible yo have a failed egr sensor or circuit