So i got my ram in oct of last year and ever sence when the temp changes outside, when i start my truck it will knock and then check engin light will come on and give me cylinder 6 missfire. After the truck warms up the knock goes away. I have changed plugs, the coil and injector. The dealer says it might be carbon. Any ideas?

 

Welcome to the site. carbon? I doubt it but you can try running some Sea Foam through the engine and see what you get. Have you check the electrical harness really good?

 

Thanks glad i found the site. I looked and did not see anything... I just don't want to rip everything apart.

 

I totally understand that. I would swap plugs and coil with those on another cylinder one more time just to be sure. Make sure that electrical connector is on good and locked in place.

 

I have done all that. Maybe im just missing or overlooking a loose wire. I just don't understand why it happens with a big temp change?? Then goes away after it warms up.

 

I am starting to think i messed up... I have been running 87 octan in my truck.. Not even thinking about it. Hope i did not f it up. 93 from now on tho.

 

yep, seems like most who lose a cylinder are those who run 87 octane for a long period. Let's hope that's not the issue.

You don't have to run 93 though, there is no benefit to running anything over 89 on a stock tune. Seems like those lousy 2 octane makes all the difference...

 

Well it only happens when there is a temp change and when the truck is first started, after 10 min it goes away and runs fine..... SO i hope it something else. I also noticed that my cooling fan has been staying on all the time now...?

 

Sticking lifter perhaps?

 

Thats what the dealer tried telling me. saying it was carbon making it stick and then after it warms up it loosens the carbon up alittle.