Ram 2500 loss of power and fuel efficiency

I have a 2012 Ram 2500 (5.7L Gas) that has had a dramatic drop in fuel efficiency (from 12 mpg to 8 or 9 mpg) for the last week or so. This has been accompanied by higher RPMs than normal to maintain speed, especially on the highway. I am not the best at routine maintenance and thus initially suspected a transmission fluid problem. I completed a fluid change but no difference. My nest step was going to be plug and run a injector cleaner through the gas tank but I wanted some outside opinions. I am look for possible solutions before I start throwing parts and money at it. Any help would be greatly appreciated.

first couple of things i would do, is check tire pressure, see if break calipers are working properly and then go to an autoparts store and have them check for stored any codes.

Have you had any unusual smell from the catalytic converter. Sometimes they will start to clog up and cause the same problem that you are describing. Just a thought


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If no check engine lights, I would be looking at the PCV system for any hose leaks or stuck valves. If overdue for a PCV valve change, I would throw a new one in and go from there.

Bad cats or even a EGR valve "should" be throwing a efficiency code for the check engine light if a problem

Huntergreen: I keep the tire pressure+/- 5 of factor recommendations and if it was a brake issue I would have expected a noise coming from them and there is not. I will check to ensure the wheels spin freely.

Whetrick1: no smells coming from the truck at all, is there another way to check the converter? I do not have any check engine lights.

Hootbro: as mentioned before, no check engine lights right now. I have had an emission light before but it went away after being reset, just figured it was the gas cap or something. I am sure PCV valve needs changed so I may start there, how do you check the system for leaks and locate them if present?

Thanks for all the tips so far, I will try to keep everyone updated once I find a solution.

If no check engine light then the cats should be alright unless you lose power going uphill or when the engine is under a load.


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eric.smith7304 said:

Hootbro: as mentioned before, no check engine lights right now. I have had an emission light before but it went away after being reset, just figured it was the gas cap or something. I am sure PCV valve needs changed so I may start there, how do you check the system for leaks and locate them if present?

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I would change the PCV valve first. Then perform a visual inspect of the hose from the PCV valve to the intake manifold locking for any cracks, breaks or significant wear.

If the hose looks fine and the connections are solid, I would let the engine idle and using either a carburetor cleaner or even brake cleaner, lightly spray around both ends of the hose and eventually over the length of the PCV hose listening for any change in idle or stumbling of the engine. The PCV hose is under vacuum and any vacuum leaks would be picked up by ingesting the somewhat flammable cleaners previously mentioned.

eric.smith7304 said:

I have a 2012 Ram 2500 (5.7L Gas) that has had a dramatic drop in fuel efficiency (from 12 mpg to 8 or 9 mpg) for the last week or so. This has been accompanied by higher RPMs than normal to maintain speed, especially on the highway. I am not the best at routine maintenance and thus initially suspected a transmission fluid problem. I completed a fluid change but no difference. My nest step was going to be plug and run a injector cleaner through the gas tank but I wanted some outside opinions. I am look for possible solutions before I start throwing parts and money at it. Any help would be greatly appreciated.

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I had that recently, I Did the cheaper easy thing first, take out intake sensor, blow it with air and wipe it. If it's dirty your engine reads that there is no enough air and will adjust accordingly. Try it and tell us how it works.

Update

I finally got a check engine light. While driving the RPM jumped up to 4500 in order to pull a hill (not normal) and the engine threw a P0305-Cylinder 5 Misfire Detected. Since I was over due a plug change I wen ahead and did that and swapped the #5 coil pack to the #3 position. While I was at it, I pulled all the injectors and cleaned them off with seafoam, but none of them looked bad. Once completed, went on a test drive with no noticeable difference but no fail codes. Forced the RPM up to 4500 and it produced the same code. Swapped the #5 injector to the three spot and tested again and forced the RPM up again. This time I got the same fail code plus P0201, P0203, P0205, P0207-Injector circuit open cylinder 1, 3, 5, 7. Reset the codes several times on the test drive and would run it up again, each time it produced the same set of codes. Now I am concerned it is either a wire harness issue or PCM problem. Did a quick check of the wire harness and couldn't see any damage but it was late any I didn't look too hard. Any thoughts??

I don't think there's any way to check your pcm. You can try cleaning all of your connections and see if that helps.


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Is it still under the power train warranty.. If so it might be covered.


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whetrick1 said:

I don't think there's any way to check your pcm. You can try cleaning all of your connections and see if that helps.


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You can back probe at the PCM connector with a scoped meter and check for injector pulse grounding to see if the PCM is performing that. Can also do the same thing to check the wiring from the injector connector to the PCM.

Also, there should be a common always hot 12V on one pin of each injector harness with the PCM providing switch side grounding.

"Swaptronics" of parts only takes one so far before high level testing is required. I would not call the PCM without checking for injector pulse ground coming out of the PCM first.

So after doing all that I could, I went to talk to my local Dodge dealership before I started looking at the PCM. Goo thing I did! They had another truck in the shop with the exact same symptoms and it was found to have a worn camshaft. It looks like I'm doing a top end on this truck now!


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Well at least they're going to take care of it for you.


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eric.smith7304 said:

So after doing all that I could, I went to talk to my local Dodge dealership before I started looking at the PCM. Goo thing I did! They had another truck in the shop with the exact same symptoms and it was found to have a worn camshaft. It looks like I'm doing a top end on this truck now!


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By chance can you let us know what brand and type of oil was used for your oil changes?

Not the first time I have heard of worn cams on these Hemi's and a common denominator was a low moly content oil was used even though it met the factory specs.

Hootbro, I bought the truck used at 50K miles and the dealership did the first two years worth of oil changes. After that I have been using a mixture of Firestone oil changes and doing them myself with Castro High-mileage. On my last oil change I did have a problem with the old oil filter seal staying stuck to the engine then the seal failing a few minutes down the road. I lost all my oil but shut the truck off quickly. I believe that accompanied with me not always getting the oil changes done on time contributed to the cam/lifter failing. When I do the maintenance I will post pics.


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You my friend just need to go lease a truck.. Or make sure u have a warranty.

eric.smith7304 said:

Hootbro, I bought the truck used at 50K miles and the dealership did the first two years worth of oil changes. After that I have been using a mixture of Firestone oil changes and doing them myself with Castro High-mileage. On my last oil change I did have a problem with the old oil filter seal staying stuck to the engine then the seal failing a few minutes down the road. I lost all my oil but shut the truck off quickly. I believe that accompanied with me not always getting the oil changes done on time contributed to the cam/lifter failing. When I do the maintenance I will post pics.


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Thanks for the info.

Sorry, this is a little long. Seems these engines have a history of burning cams, and at the #5 cylinder at that! There was a back order of some 2500 units for the lifters. Finally got mine and got the cam replaced, easy enough of a task. Followed the Hanes manual for timing and torques with no issues...until I tried to restart the truck. The thing would barley run and when it did run, I had to keep my foot about half way down to maintain 2,000 rpm (the lowest I could go without dying.) my first thought was timing so I pulled everything back apart and checked it, spot on per the manual. Checked with my local dealership and they confirmed it was correct. Re-assembled and tried it again, still sounded bad but better than it was. Pulled all the plugs and they had heavy carbon build up from me trying to clean the heads with sea foam. I did one side at a time and started it while each side was out. The truck seemed smoother with the driver side in verse the passenger side so I pulled the valve cover to check for a dropped lifter rod, all were properly installed. Now I am stuck! Anyone have some ideas? As usual, thanks for any help and suggestions.


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Oh, photos of the old cam!










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