Looking for advice and opinions (I guess that's why we are all here)....I have a 03 Dodge 2500 with a proud 135,000 miles that has developed it's first problem, after idling for a short time the idle begins to fluxuate around 50 to 100 rpm's (sounds like a v-8 with a big cam), after reading through these treads until my eyes where bleeding.....I assume the lift pump is the first item to look at being others have mentioned lack of fuel pressure will lead to my issue. I've also notice that some people discovered that injectors can also act like this. So my question/request for advice is being that both items can add up to a large amount of $$$$$, with the description I have provided which part would you replace first? Anyone know what brand of injectors to go with?

That's everyone!

 

Sounds like a sticky FCA. Very common problem.
Do you have access to a scan tool?

 

I do not own a scan tool, i did however go to the local parts store (AutoZone) and used theirs, but i was looking to double check and clear a code i was getting (P0234), which I know is a Turbo over boost. I went down the road of possibly a bad wastegate actuator, but the symtoms don't excatly follow what a bad wastegate would do, and i have the Edge brass elbo in my turbo housing which creates a higher than stock boost....But i could be wrong and opening to being corrected.

 

How's the power when you get on it?
You use less fuel at idle than under load. If it idled fine but fell flat then I would suspect a fuel supply issue.
As I mentioned FCA (Fuel pressure regulators) are very common to fail as the engine ages.
Basically the regulators get sticky and can't react fast enough to respond the the ECM commands. What happens is the the fuel rail pressure gets very erratic. UP, DOWN, UP, DOWN and with that goes the RPM.
If you can get you hands on that scan tool, monitor the DESIRED fuel pressure and the ACTUAL fuel pressure. If the desired is constant and the actual is varying by more than 500 psi (compared to desired) I would change the FCA. Easy to change but $350 dollar part.

 

The power seems fine, just pulled a flat bed trailer with a couple quads on it and one in the back of my truck over the coast range yesterday, the trucked acted normal....I like your idea, I think i should change out the FCA even if that's not the issue. I have enough miles to justify the purchase. I found a FCA for $145 so i'm thinking about the Air Dog at the same time for security sake.

A scan tool would be a cool little glove box gadget! Damn, i need a sugar mamma!!

Thanks for the help rabbler!

 

That's a very good price!
The Air Dogs sound like very good units. If you still have the original fuel filter mounted lift pump its not a bad idea.