I've got a 2002 2500 5speed that's developed a vibration or a miss under light acceleration. This all started after the wiring fried on my relocated ddrp. I've said since repaired the wiring but sometimes the truck acts like it has either a leaking injector line or its getting air in the lines. However its only noticeable at 30 mph in 4th gear putting through town. I dont have any codes except for a p0177 and I know there's no water in the tank or lines. One last thing as soon as I accelerate or downshift to raise the rpms it goes and away. Any help or suggestions would be greatly appreciated. Thanks

Edited June 9, 20159 yr by okredneck

Or a better fix yet drive through town in 3rd gear to keep your RPMs up higher. A diesel engine in general doesn't like to be "lugged" around town

where is your fp sending unit mounted

have you had your battery terminals loose lately, if so you may need to recalibrate your apps. i mean if your sure that LP cutting outs not the issue and your sure your FP is staying up then lets move on

Edited June 10, 20159 yr by rburks

I dont try to lug my truck but with how its geared if I'm in 3rd I'm running 2000 rmp @ 30mph so unless I'm loaded down I'll leave the truck in 4th and coast through town. It only happens when I lightly accelerate but when I give it a little more peddle to go from 30 to say 45 it doesn't do it at all. My FP line is connected to the injection pump and hard lined to the gauge. I know its not the best setup with out an isolator but I haven't had a chance to fix it. And yes I've had the cables loose to repair the extension line and again to replace the alternator so twice in the last few days and I never reset the apps. Didn't even think about that. Thanks

what your describing sounds to be to be electrical, i could be wrong. it could be else where. ...like maybe the computer in top of the Vp44 or maybe something that controls it . but the fact you don't have any codes is confusing..

 But if you have good steady FP it must be up front around the fuel system

 

I dont try to lug my truck but with how its geared if I'm in 3rd I'm running 2000 rmp @ 30mph so unless I'm loaded down I'll leave the truck in 4th and coast through town. It only happens when I lightly accelerate but when I give it a little more peddle to go from 30 to say 45 it doesn't do it at all. My FP line is connected to the injection pump and hard lined to the gauge. I know its not the best setup with out an isolator but I haven't had a chance to fix it. And yes I've had the cables loose to repair the extension line and again to replace the alternator so twice in the last few days and I never reset the apps. Didn't even think about that. Thanks

IM Thinking this might be your problem,,i hope it is anyway.....JUST UNHOOK BATTERY TERMINALS FROM BOTH SIDES ATLEAST  NEG- ON PASS SIDE AND LEAVE OFF FOR A FEW MIN. THE REINSTALL. THEN TURN KEY OVER TO START POSITION BUT DON CRANK MOTOR, PRESS DOWN SLOWLY ON FUEL PEDAL ALL THE WAY TO FIREWALL OR TILL IT STOPS THEN SLOWLY RELEASE PEDAL BACT TO TOP, REPEAT THIS STEP 1-TIME AT LEAST AND YOUR DONE.........Good luck 

When I first noticed it I immediately thought I would be replacing another IP but I'll reset the apps in the morning and let y'all know what happens.

The only other thing I could think of is an injector problem since it almost feels and sound like I've got an injector line cracked open slightly on one cylinder but I've checked for leaks and haven't found any so I know its not a fuel leak.

OK,,,, HOLD IT..  i thought it was just like a short pause or heekup   ....I guess i have totally misunderstood you. 

still ...I really don't see it being an injector unless it miss  especially when cold, and  smoke,,,does it run and idle smooth

 

when your lugging around and it act up do you see any smoke,,this is important

Edited June 10, 20159 yr by rburks

ITS so hard to tell without hearing it in person....here is bout all i can tell you, if its not electrical, if its missing and jerking it very well could and injector dripping cause it wore in check valve/seat and not closing all the way. this would be noticeable at extended periods of low to no throttle.

  the nozzle will drip fuel into combustion chamber its not burning this will cause blue smoke,  if you don't have smoke this is probably not the issue..it should smoke and idle rough after it sets overnite till you run it down the road and it burns off the fuel.

 

    another thing you might want to consider is valve adjustment,,,I MEAN THEY WOULD HAVE TO BE WAY OFF BUT ITS POSSIBLE IF THEY'VE NEVER BEEN ADJUSTED

 

  LET ME KNOW WHAT YOU FIND

Will do

I would figure there suction air leak some where now. Drawing air into the fuel system on the suction side of the pump. Because if it was a pressure side like you would fuel dripping from the truck.

I would figure there suction air leak some where now. Drawing air into the fuel system on the suction side of the pump. Because if it was a pressure side like you would fuel dripping from the truck.

 

He says that his FP is good and consistent, no drop when the "miss" occurs.  so IDK, Like i told him, its hard to diagnose without being there in person and hearing/seeing it. BUT: if it was sucking Air that should be the only time that it didn't do it was under very light throttle. don't you think  

Apps reset solved the problem thanks for the y'all

HEY, YOUR WELCOME  

Apps reset solved the problem thanks for the y'all

 

Couple of thing to be aware of. I would check the alternator AC voltage (AC noise level) and be aware that the APPS sensor might be wearing out if so then the P0121, P0122 or P0123 might come in the near future. All make sure to remember disconnecting the battery only does one thing in dumps the calibration limits of the APPS sensor. It does not reset error codes or reboot the computers (ECM, PCM, or VP44).