Hello all!


I have a 2003 4.2l f150 with a missfire on cylinders #2 and #6. I have verified spark plugs and wires are good. I have pulled the ignition coil and tested ohm readings with multimeter (per various youtube videos) and i am getting good readings there (i think). I have also tested other spark plugs and wires that are known to be good on the same coil with no spark at the ignition coil. I am seeing where some people are pointing to the pcm next. Is this the next step in troubleshooting this dilemma or what? Please and thank you for your patience and ideas!

 

1st off , how did you determine that the plugs and wires were OK ?
Did you switch the plugs to different holes and the miss stayed the same 2&6 ?
And did you swap the wires ? Were any of the boots soaked w/oil?


I would look a little closer @ the coil, both 2&6 share the same components.
You can pick up a coil for 25-50 bucks
I imagine the ECM is going to be a bit more expensive.... and you will need to have it programmed.

 

thanks for the fast reply... I did switch the plugs and wires to other holes and the miss stays on 2 and 6. i have the coil on my desk right know and have looked over it several times but don't see any cracks or anything. When i put it on the multimeter i get readings through the nipples (is that what they are called?) not sure if this test tells me anything, but i am getting a reading there.

Also, I replaced the plugs and wires about 2 months ago. Just recently started missing again. At that time the miss was on 2 and 6 and was fixed... I move the wires and plugs around and they work every else... just not on 2 and 6. Can you determine whether a coil is bad with a multimeter? Not worried about the money (20 - 50 bucks is not going to break the bank) but don't want to buy one unless I have too. Ofcourse I'd much rather it be that instead of the pcm...

 

Heres a link to testing a 4.2 ing.coil
http://easyautodiagnostics.com/ford/...he-coil-pack-1

 

Was looking at that last night! Glad its a reliable source... I don't have the test light though... guess i need to get one. Im at the point of checking the juice going to the coil now...

 

I know a bad coil can cause plugs to go bad without any "sign". I had a misfire on cylinder 6 that would be corrected with a new plug. 200-300 miles later another misfire on cylinder 6. After I changed the plug out 3 times I replaced the coil and problem fixed. Good luck

 

If 2 and 6 are down, and the ign system is working, then I'd certainly do a compression test on that engine. Throwing all the crap in the world at it won't fix it if it is an internal engine problem. Before I did another thing, I'd pull all the plugs and do a test. What have you got to lose?

 

He replaced the plugs and wires 2 months ago and fixed the miss .... now its back. Does compression come and go ?

 

thank you all for your replies... lets assume it is the ignition coil. Could a misfire come and go on the same 2 cylinders? also, can compression come and go? It seems to me that a miss would be more likely to come and go... but again not too-much experience with this. Thanks again!

 

You got it right.
compression is mechanical.. it wont come and go....
But a coil can be affected by moisture and heat....
I'm leaning towards the coil...