Hello everyone ive got one of the biggest stumpers i have ever come across in my life.

First off i have replaced:
cap.rotor.plugs.wires.iac.crank position sensor.entire exhaust.both o2's.timing set.and finally the coil. I am 100% lost from here. I can here what sounds kinda like an exhaust leak up by the manifold but the things i do know are that the belly pan and the head gaskets have been replaced by the PO. The code comes on always at idle and it does idle pretty rough. The code will come on and then within the next 100 miles it will go off on its own then repeat the process. It sounds like a sensor is getting intermittent but i dont think there is anything else related to this problem that i havent already replaced. If anyone has any ideas that would be awesome. Like i said im lost at this point.

P.S. compression is good spark is there on all of the cylanders and i have tested fuel pressure. all tests have passed with flying colors.

 

What engine? Obviously not a 4.7

What plugs are you running? Pull #3 and check it. How's it look? Just because it's new doesn't mean it isn't damaged or bad out of the box.

Could also be dirty or leaking injectors?

 

its the 3.9l v6 sorry totally forgot that part lol. and when i pull the plug out it looks like its not fireing. Its clean and white. But i have tryed 3 different plugs in it and to no avail. first i was running autolites. then i switched to ngk. then i from this forums information put in the autolite 2568 or something random like that. its i guess one step colder to prevent pinging i guess? how do i test the injectors? just pull them off and look in them or????

 

he just replaced the plug

I know this guy needs help but he starts new threds all the time looking for answers to the same problems.

Like hello I still heve a problem someone answer me.

Getting pushy gets you no answers.

We try thats all we can do.

 

no bro i dont the idle stumbling was what i had before and thank you very much the iac fixed that. the p0303 code was a whole different issue that was only mentioned in my first post and was never when into depth. i have only started 3 threads here and one was idle stumble and the other was e-brake related and this one is misfire on cyl. 3. sorry my truck has so many problems but thats no reason to bash me.

 

I would pull #3 injector and a switch it with another.
Reset the computer and see if the fault travels with that injector.

 

No worries mudder dak you have just as much right to start a thread as anyone. What does the code say? I don't have my manual with me right now so I can't look it up.

 

Thats a good idea i never thought to try that. I did test the injector with a ohm meter but that would really test it good. How hard is it to do such a job? I have never pulled an injector off before?

And P0303 is misfire cyl. 3 detected. Thanks guys!

 

Yeah, that's a good idea to swap the injector. It seems like that is the only thing left to do. If it's not that I don't know what else it could be seeing it is specific to that cylinder.

 

+1. If youve switched other things out to no avail then this is another route you can take.