I noticed driving to work this morning that my truck loses power at about 2500 RPM. It's like it just stops adding fuel. It will still accelerate and rev to 3000 RPM but it does so very slowly from 2500 to 3000. I notice small puffs of black smoke coming out the exhaust when this happens. It doesn't buck or pop or anything like it's missing, it just hits a wall at 2500 RPM. The weird thing is that it only happens in 4th, 5th, and 6th gear. It runs great in 2nd and 3rd. Anybody have a diagnosis?

 

lower gearing in those gears check your fuel and air filter first mite be clogged. also check your fuel pressure mite be a fuel pump problem. that year model i when they started putting them in the tank so not sure where the pump is could be in tank or at motor

 

The pump is on the fuel filter canister. I don't think the fuel filter is even 5000 miles old. Air filter is fine. I replaced that about 200 miles ago. I checked the filter minder this morning and it hasn't moved.

 

Sounds like a weak lift pump to me.Do you have a way to check the fuel pressure?That style lift pump is gonna fail eventually,might as well go ahead and replace it if you have the money.

 

My question is why are you running your truck up to 2500rpm then 3000when shifting or what not.
Truck is probelly defueling at 2500rpm in 4th 5th and 6th gear. Even though it keeps acellerating to 3000rpm.
Really your truck is trying to protect itself.

 

I was waiting for somebody to say lift pump. That's what I was figuring but I didn't want to say that and give anybody a preconceived notion. I wanted a fair and unbiased diagnosis. How could I check the lift pump pressure?

I don't routinely shift at 2500 or 3000 RPM. I only did it this morning to make sure she still runs good. I normally shift below 2000 RPM. The truck is not trying to protect itslef because it hasn't thrown any codes. It ran perfectly fine just last week when i revved it up to 3000 RPM to clean her out.

 

Bump... Anybody have a similar issue?

 

The truck wont always throw a code. If your lift pump was going you should have gotten a code also. But as this is not the case I would be looking at your airfilter.
I would also be looking at your fuel filter.

Your fuel maybe suspect also.
Drain some fuel into a clear clear jar from your filter drain and swirl it around and see if ther is water or other debris in it.

Have you noticed a drop in milage or performance?

Reving your truck to 3000RPM to clean it doesn's really do anything. Burning the carbon out is an old wise tale.

Reguardless lets try and work you thrue this situation.

 

As I stated earlier, the air filter is fine. It's not sucking down the filter minder at all. Obviously there's a drop in performance past 2500 RPM. It runs fine until then. As for the drop in mileage, it's too early to tell. I will get a fuel filter today after work and put it in to see if that helps. I will also drain some fuel and take a look at it tonight.

 

those filter minder sometimes don't work all that well. I had a completely block air filter by packed snow and or ice a few times. The minder never pulled down at all. Those filters were blocked solid one had 4 inchs of compact snow stuck to it, the other one was frozen solid from road spray. If you havent allready pull your air filter it's worth a check.

 

The 3rd gen doesn't start to defuel until 2900 rpms...

Also an int lift pump wont throw a code, and really a bad one will only throw a code at the CP3.. the ECM doesn't monitor LP FP.

 

Sir, the air filter is fine. Please refer to post #3 above. I changed it only 200miles ago. I know the filter minder works because it was sucked almost all the way down with the last air filter I had. I know you're only trying to help and it is much appreciated, but let's move past the air filter.

 

You need 3 things to work in order for your truck to run, fuel, air, electical.
what you are describing can be a problem with either of the three,

Check your fuel pressure if that doesnt work then take it in to the dealer to have them scan it for any other problems.
Not all codes will show up on the key on, off,on check.
Or the hold the trip reset button down and key on for a diagnostic check/codes.
But from the sounds you are ether running out of fuel or air. So check those two.

 

Ok, another little bit of information to confuse you. When I drove home last night, it ran much better, still not up to 100% power but probably 90%. Driving to work again this morning, I had the same problem I had yesterday, it hits a wall at 2500 RPM. This makes me think that whatever the problem is, it's dependant on the ambient temperature because it's in the lower 40s when I drive to work and upper 70s/low 80s when I drive home. I can't figure out why the temperature would affect it though.

 

Without some gauges to see whats going on its gonna be hard to diagnose.A fuel and rail pressure gauge will tell alot.Regardless,the filter mount lift pump is a poorly designed piece of you know what that Dodge finally replaced with the intank pump.It can work perfect and fail out right or can slowly become weaker and weaker till it fails.The colder mornings and the fuel being thicker could be the culprit if the pump is weak.Being you don't have any codes or gauges its a guessing game at this point.If you have warranty let the dealer give it a look with a Starscan or DRB.Upgrading the lift pump should be on your list anyways as preventitive maintenance before it leaves you stranded on the side of the road with no power!