Hi I recently replaced all of my spark plugs in attempts to get rid of the check engine p0303 code that i'm getting. I really didn't think this would make a diff but my mechanic reccomended it.. wel lit didn't work, I still get the code.

All of this is happening after I blew my #3 spark plug.

Is there something usual that happens that I need to fix in addition to putting in heli-coil?

I've heard its the coil, spark plugs(no), injector or spark plug wire.. How can I tell which one without replacing all of them?

Thanks

 

you can try and swap #3 and#2 coilsand seeif the code changes

 

How do I swap the two out?

My truck has two coil units.. one on left head and one on right head.

Thanks!

 

What year and engine is your truck?

 

Truck is 1998 4.6l V8

 

You should have coil packs on each plug.

They are the black rubber boots over each plug.

He is saying take the suspected bad one and switch it with another spark. Your code should change if the pack is bad.

 

4.6l's have a coil pack for 4 plugs were as the 5.4l has a coil for each plug.

anxvariety, i would suggest that you get a repair manual, i prefer the haynes manuals but thats my choice. either one has the testing procedure for the coils. i 've found ford performance coils for $52.00 at carquest and accel performance for the same from performancetruck.com. i 've been fighting a miss fire for about 10,000 miles. it's nuiasance but the trucks never failed me.

other common causes of the miss fire is moisture in the hole through the head. the spark plug boot allows water to collect in the hole and shorts out the plug. cause are leaking heater hose connections, or if you wash your engine compartment often.

 

D'oh...you're right

 

My guess is you have a bad wire if they are original.Try a junkyard and get 1 wire to make sure, then if that is it buy new wires the factory wires were not to good. I used MSD 8.8 Superconductors,they cost around $125. a set.
GOOD LUCK, hope this helps.
PS use dielectric grease on both ends of wires

 

did they pull the head to put in the heli coil, if not could have a peice of metal between the valve and valve seat.