Ok so i have a 5.4 2006 xlt, i have 120k on the motor. I had new plugs put in(no plugs cracked), and i did the coils. After the work was done p0300 came up i put new coils in angain, cleaned the air filter(amsoil dry filter), and i replaced my fuel filter about 30,000 miles ago. Should i pull all the plugs and put new ones in.
Any ideas on how to fix this?
Thanks yall

 

wait until you get the p030x code that identifies the cylinder. Do you have a noticeable miss? What plugs did you use? I'd get it to give the cylinder code if it were me before you throw any thing else at it..

 

P0300 code indicates random misfires and I've only seen it with more than 1 cyclinder. A single Cylinder should throw a single P030x without a P0300.
Jethat is right..wait to see what hatches.

JETHAT--like that MACH1 there. I have a 71 in my garage listing but not stock looking..

 

Yep, -PO300 "Random Misfire" just informs the tech to mode 6 it, - the info is recorded in cylinder history. Does us absolutely no good, we don't have that $10,000 diagnostic equipment to read it's mind...

I'd push the engine until the CEL blinks 5 or 6 times. Once that happens, do this one more time, - maybe the scanner will give you better direction once that's been achieved. It's worked in the past.

Otherwise, it's off to the dealership.

 

ok so i worked the hell out of the truck still just p0300. At idle you can tell that its missin, i used the champions.
Well i dont know think i might have to end up bringing the truck to a shop

thanks yall

 

You may want to pull the Champions out and put Motorcrafts back in. Not everyone is having good luck with the Champions.

 

X2.. I wouldnt use Champion plugs myself in my lawnmower.. I would still get it to give up the code. It will eventually. Try going up a hill slowly that might do it put a load on the engine..

 

thanks guy ill get the champions out, and pulled 28 foot boat with it yesterday and it still just said p0300

thanks yall

 

Yes, remove those Champions lol.

Run ONLY - Motorcraft, Denso's or NGK's for that engine. NOT Autolites!

 

No Denso or NGK for the 3v.

 

Crap! That's right, - I'm mistaken, that's for a 2 valve not the 3 valve. Thought the OP had a pre 04 model 2 valve for some reason.

The Champions can cause headaches in the 3V as well. There you better off with the Motorcrafts IMO.

 

thanks guys im goin to get them out this weekend