Hi guys, i have a semi-urgent question for ya.

Im trying to get my '99 5.4 to smog and the day i take it in (today) it comes up with a P0304 code. After reading a bunch of other misfire posts, i swapped out the COP with #1 and took it for another drive. Now im getting a P0300 code with NO MORE p0304. What could the problem be?

It does have the typical low RPM stumble and minor hesitation, but overall its running okay. Could a bad plug have damaged a coil or vice versa now causing multiple misfires?

Reason its kinda urgent is due to the fact that i am 250 miles from home since the truck is being stored at a friends place. So i need to get this diagnosed/fixed/smogged/to the DMV tomorrow. Probably not going to happen, but its worth a shot. Oh and to add insult to injury, i dont have any proper tools to fix this, so maybe a shop is my best bet, but hopefully one of you guys has some insight into this problem.

Thanks a bunch!

 

If it has been stored long it could be ugly gas, or the injectors are gummed.
Put some injector cleaner in it and take it out and run the snot out of it. Then put in some really good gas.

Also check the connectors to the injectors.

That would be my $0.02

 

Thanks for the quick reply. I'll try that and go from there.