P0303 Cylinder 3 Misfire Detected

[hndgnr]

hi everyone my first post not my first visit.This forum helped me heck made it possible to diagnose and replace a sensor in my tranny. now I need more help I have a P0303 Cylinder 3 Misfire Detected code.
can someone help me understand what this means? could it be a fuel injector problem? I have been having some sputtering or hesitation on take off. seamed to be getting worse. So I was thinking the fuel injectors needed replaced so I ordered some yesterday, then today it sputtered quite bad then the check engine light came on. then it is running back to the way it has been. 1998 4.0 sohc thanks ahead for the help Jerry

 

[lighttech]

MIsfire

I think that it may have been a bit rash to run out and order new fuel injectors. A misfire can be caused by any of the following:
1. Fouled spark plug.
2. Bad ignition wire.
3. Bad (burnt) valves.
4. Bad head gasket (usually accompanied by white smoke out the tailpipe)
5. Electrical connection issue at the injector, or computer.
6. Bad computer.
7. Several other things I cannot think of right now.

Ignition problems are the most common, and easiest to troubleshoot. Pull out the plugs and take a good look at them. When was the last time the wires were changed ? If you do not know or can't remember, now is the time. If nothing obvious is found with the plugs, test fire the spark plug. You will need someone to help you with that.

Next would be a compression test to eliminate valves or other mechanical problems.

If still nothing found, then check injector coils for continuity. Check wiring for corroded connections at the computer.

If after all that, and you still cannot find the problem, only then should you consider changing an injector.

Hope this helps. Good luck.

Craig