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2002 Dodge Ram 2500
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Discussion Starter · #1 ·
Hey everyone, I'm new to owning a Dodge/Cummins. I just got into a 2002 Ram 2500 a few weeks ago. It has 179,000 miles on it and is completely stock except for the BHAF. The thing starts and runs like a top except it has an intermittent miss at idle after it is warmed up. It idles perfectly smooth when I first start it up, but after I drive it far enough to get it up to operating temp, it has a rough idle. The goofy thing is if I shut it off and start it right back up it will idle nicely for a couple minutes and then starts acting up again. Also, if I drop the auto trans into gear it starts to idle perfectly smooth again. It doesn't take much of a load on the engine to smooth the idle out either. Sometimes turning on the headlights and stepping on the brake pedal makes the alternator work just hard enough to smooth it out. Other than that it runs amazing. I already checked the fuel pressure and it sits at about 18 when idling and drops to about 14 at 2000 RPM. I'm excited to learn from all the Cummins guys here!
 

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Welcome to the forums. There's lots of good information here.
Congrats... nice truck.

You might scan for stored codes with a good scan tool like a Snap-On.
Does it still have the original lift pump?
I see you've checked the pressure, but you'll want to consider installing a full time fuel pressure gauge.
These trucks need one.
Pressure should be 14 pounds, not dropping below 10, on a stock truck.
The FP you posted is a bit high.
Also, lift pump could be dropping out if it's starting to go.
 

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Welcome.. That is often an injector is dirty or worn out. Exactly what mine did, only I had a lot more miles.
 

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PS please fill ou signature with truck info. Does the APPS have a pig tail sticking out below the bell crank bracket?(Tiimbo apps), or does the plug go up under it.
 

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2002 Dodge Ram 2500
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3 Posts
Discussion Starter · #5 ·
Welcome to the forums. There's lots of good information here.
Congrats... nice truck.

You might scan for stored codes with a good scan tool like a Snap-On.
Does it still have the original lift pump?
I see you've checked the pressure, but you'll want to consider installing a full time fuel pressure gauge.
These trucks need one.
Pressure should be 14 pounds, not dropping below 10, on a stock truck.
The FP you posted is a bit high.
Also, lift pump could be dropping out if it's starting to go.
Hey thanks. I did a code dump through the dash display and the only engine code was P0234. That looks to be boost pressure over limit. So maybe my map sensor is out of range or maybe the waste gate is actually sticking. I need to get to the bottom of that. Doesn’t seem like that would cause a rough idle though. And I’m definitely going to be putting a fuel pressure gauge on it soon.
 

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2002 Dodge Ram 2500
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3 Posts
Discussion Starter · #6 ·
PS please fill ou signature with truck info. Does the APPS have a pig tail sticking out below the bell crank bracket?(Tiimbo apps), or does the plug go up under it.
Hey I looked under the truck and there seems to be a wire harness between the bell housing and the crossmember. Is there a way I can post pictures for you?
 

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Sure enough, just use the tools there under your post.
 

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I have that issue where it idles rough after it’s warm too,idles fine when cold,I’d like to figure it out,I’ve got 15 psi 1/2 lines all the way,newer rv275s,I’m going to try new tubes,orings and washers and see what happens
 

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It sounds like it's vp44 related.
Do you know if it's original.
That's a lot of miles on a original one.
 

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Mine acted like that at about 500k mi from worn/carboned up injectors.
 
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