As the title states, I have a code P0303 on my 1998 Ranger 4.0. Its a Cyl #3 Misfire. Iv'e gone through and replaced the spark plugs twice, spark plug wires, fuel filter, pcv valve, and coil. No luck with anything as of yet. I can not find a vaccum leak present, I am also gonna replace #3 injector tomorrow when it comes in, along with the Intake Manifold gasket. If anybody reading this has fixed/ or has some input, it'd be Greatly Appreciated. It's my only way around and i need of a fixin. Thanks

Edit: When i first start it in the morning, it runs great like nothing's wrong, but once it warms up thats when the severe hesitation and lack of power starts. Also when i stop somewhere i can smell coolant.

 

Anybody??

 

Pressure test the cooling system when hot.
Prob a bad head gasket.

 

Okay thanks

 

I was wondering if you ever got this cleared up? I had this same code about 7 months ago and believe I changed the oxygen sensor and it fixed the problem. Unfortunately the check engine light came on again yesterday after my son borrowed the truck and now the same code is coming up.

 

I don't understand how replacing an o2 sensor has anything to do with Cylinder Misfire.
What engine is it? Have you checked the wires and plugs?

 

I thought that is what I previously changed to get the code to clear. This time, I just went ahead and changed #3 spark plug and wire and that fixed it.