Truck started idling rough yesterday at traffic light and starts jerking around 45 mph, code is P0305. Ohmed out the injector for #5 cylinder (26.4) ohms, engine was warm when I checked, is this in spec?

 

You will need to look in the FSM for the ohm spec. If it checks out start simple. replace the spark plug with an el cheapo from the parts store and see if things improve.

While at the store rent a compression tester, is the spark plug doesn't help then run a compression test just to rule things out.

If that checks out then it must be fuel if the issue is only with #5.

 

ohm out the spark plug wires too. all 3 should be fairly close. if one is way off from the others, that's probably your issue

 

I ohmd out the injector with the motor cooled off, read15 ohms, I ohmd out the injector for #3 cylinder, 14.6 ohms, so maybe I'm on the wrong trail.

 

did you find what the spec was in the FSM?

 

I saw on another thread that 14-16 ohms is good, I pulled the coil pack off, but the boot didn't come with it just the coil and a long spring, so now I have no clue as to how far does the spring fit in the boot and also does anyone know what the spec is on the resistance of the coil?

 

Any oil leaks?

Sent from my iPhone using YotaTech

 

No, may I ask what would that cause?

 

Ive heard an oil leak in the top end(rings, valve seats) can cause your plug to foul and cause a misfire. http://www.obdii.com/articles/Diagnosing_Misfires.html Sent from my iPhone using YotaTech

 

Gotcha, didn't get an opportunity to pull the plug out today, due to thunderstorms, it tripped me out yesterday when I pulled the coil pack out of the boot( on accident)

 

If the coil fell apart when you tried to remove it then it is a good bet that you found the issue. Would easily explain why the misfire was on #5 when the coil feeds 2 cylinders.

Move the coil to another cylinder and see if the issue follows it.

 

Swapped #5 coil pack with #3 and re scanned problem stayed on #5 cylinder, replaced plugs, wires, runs like a dream, Thanx guys!

 

probably a bad plug wire for sure. i had a similar issue not too long ago myself. changed the spark plugs cause they needed to be changed anyway, which didnt help. then ohmed out the spark plug wires and found a bad one.