Hello all, looking for some help from the knowledge base out there.
I have codes indicating #5 and 8 misfires. I read an old post from 2005 that suggested crank sensor is good place to start. So I proceeded to change and in doing so I found the cap had traces jumping all around inside and the button contact for rotor wasted. So cap\rotor replaced, but still misses. So back to crank sensor and found it to have very very tiny crack, yep, I gingerly replaced it. Cleared codes, drove about 6 miles, same codes came back, misfire #5 and 8. I read a post on testing injectors coils for proper resistance range and all 8 are good (doesn't mean these are plugged or partially plugged). (Those wire clips are a pita) Then I ran compression test on each cylinder all are within good average according to my dodge ram bible. (My notes are at other shop so no numbers to give). So I replaced wires and plugs, checking each gap as I go and replaced each wire following same wire route. Changed air filter and took a drive, still misses, code are same #5 and 8 multiple misfires. Today I replaced those 2 injectors, cleared codes, drove about 15 miles, no codes no engine lite, but still misses. WHAT THE HECK? I did not change ignition coil as I think if bad the truck would have starting and running issues. Misses usually start around 2000 rpm after shifting to 2nd, then I turn off overdrive and miss goes away and truck runs great, but misfires will come back if going uphill or the engine is under a load. I know it seems like throwing parts at it, but I tried to go step by step.Sorry my story so long but wanted to cover the bases. Any and all input is greatly appreciated. Thank you.

 

What brand crank sensor? Did you check the plenum?

 

Autozone duralast. All parts except injectors are from Autozone. I did not think of looking into the tb to inspect plenum. Is that about the only way to check it? Thanks for asking

 

Yes it is. The Autozone sensor could be your problem our trucks only like Mopar sensors

 

Thanks, When I get back I'll look into tb. It's just a flat tin plate separating upper from lower right?? What signs am I looking for and could it be a reason why I get multi misfits on 5 and 8??

I figured duralast was better then one off ebay, not real excited thinking I might have to buy oem and lay across motor again, it was no fun. Appreciate you reading and replying.

 

Yeah, they could have put the crank sensor just about anywhere else, and it wouldn't hurt my feelings.

When you look down the TB, if you see oil pooling in there, gasket is bad. (usually starts pooling at the back, might have to pull TB to get a good look.)

 

Get a mechanic's mirror (AutoZone had them in the plastic parts bin by the counter for like $2) ABC's like HeyYou said try to look way in the back. When I did mine (just as preventative maintenance) I saw no oil whatsoever, but when I pulled the intake off it was blown.

 

THX MOPAR and HeyYou, I'm out of town now. I'll use my lighted mirror to take a peek when I get home. This oil pooling, will it cause misfires, or is it just gonna use more oil?

 

It is known to foul #8 spark plug. You might see a little bit of oil and that is normal as the PCV valve will spray a small amount of oil. A test a liter of people say is disconnect the PCV valve line and plug it and the kegger hole. Do the same for the brake booster. Open the oil fill cap and put a piece of paper over it. It is sucks the paper the plenum is likely bad