I have a 99 Ford Expedition that started running rough, checked the codes because it is showing check engine soon light, shows code for spark plug 4, took wire off put back on and erased the code
my Ford Expedition is running rough, have replaced fuel filter, air filter, changed the oil. After running a scan it is showing with a P0304 code and when I looked that up it said misfire on number 4. I am fairly broke right now until payday next week and need to make an approximate 200 mile rt trek on Monday. Should I start with just one spark plug to see if that cures the problem? I cant really afford to buy all 8