Well, for a while I was hoping I'd gotten the diamond in the rough. Alas I think I might have fallen victim to the used vehicle market.

Recently I found that my 5.7 Hemi is using oil and I started experiencing some weirdness. I changed the oil (I think) about 2500 miles ago. I had to add a quart today. I added the recommended amount in the owner manual plus new Mopar filter when I changed it.

The other day, while at a stop light, the engine stumbled and rpm's dropped to 200'ish.

Tonight it shifted very weird into third a couple times. One time the orange engine light came on and then went off. The shifting felt like it was shifting twice into the same gear but hard. That's the seat of the pants feel.

So far I have had the transmission fluid and filter changed at the dealer, new cowl, new PCV valve in (in response to stumbling), oil change, air filter changed, cleaned negative battery cable and a little throttle body spray and wiping. I did spray the IAT sensor in the air box plenum with throttle body spray. Hmmmm...maybe I shouldn't have done that. Anyway, it wouldn't necessarily explain the stumbling or shifting weirdness.

I can troubleshoot it but I thought I'd post here to see what weirdness I should probably check out first if someone has experienced same symptoms. And yes, I did post this before searching, which is my next step.

I have the 4x4 limited with no traction control. 93K

 

Check to see what trouble code is showing.
FF

 

Well, it did it again today. Was sitting at a light, accelerated normal, then I put the pedal pretty far down to speed up and it started jerking and cutting out. Finally the mil stayed on and I was able to get the code.

P0339 - Crankshaft position sensor intermitent.

I had the battery load tested and it is fine. Interesting though it says it needed to be charged...whatever.

I looked over the wires where the loom goes between the starter and block to go up to the top of the engine (around that whole area). I did not see any broken wires or worn spots; it's all inside a protective plastic.

I read some posts here and one of them said most likely it is a bad ground somewhere. So I'll go see if I can find a bad ground. Someone quoted a $30 part which is cheap enough but I'd rather not throw parts at it.

Any other quick tips or do I need to crawl around with my volt meter checking pins like the FSM states?

 

well these engines are a DIS.. distrubutorless ingition system.. which means it uses a crank sensor and cam sensor to tell the computer when to start to fire on one and so forth.. so its saying your sensor is starting to go with a P0339.. all it is, is a magnet that reads a dead spot on the crank.. its a sproket.. its in an oil valey and needs to be changed.. magnet picks up small microns of metal..

 

I tried to get the sensor connector apart to test the voltage and such. No luck. How does that connector come off?

 

Tried some other things to get the sensor connector off but couldn't. I accidentally broke the little thumb tang off of it. I had a radiator flush scheduled at the shop anyway so I had them check it out. They said the sensor was bad and changed it.

I noticed that some other things changed as a result. When I used to coast down hill the engine rpm would be at like 1500. Now it is at 500. The fuel mileage seems to have jumped quite a bit better. I'll know how mutch after a whole tank but right now it looks like 2 mpg. It shifts smoother and seems to have more power in second and third.

Maybe the sensor should be a scheduled maintenance item...