after changing plugs, wires, and coil pac ..my check engine light light came on it took 75 miles to clear about 25 miles later went in for vehicle emmissions check...it failed with same code P0304 ...is it too soon for the secondary code to clear from the computer.......
P0304 engine code on 2002 Dodge Caravan
clearing the code fixes nothing. you need to fix the reason that number 4 is missfiring. could be an injector, vacuum leak or low compression. you need help to track it down.
There is info stating that injectors are common to misdiagnosis...also there was a code two months ago for a very small leak in the erg system ..checked hoses will look again any other ways to nail down a vac leak in the system ...i was told to check crankshaft sensor voltage Hi & lo..what else..thanks bioman