Hey guys I've been having this issue for a while now and I can not figure it out. My truck has a bad miss when cruising through town and about 35mph in 4th gear rpm is around 1500. It will do it in any gear in the 1400-1800rpm range it's just worse at 35 and 55mph. Its not throwing and codes and I just put in a new IAT and crank sensor neither have changed how it runs. I put a map sensor in it last summer so that's fairly new also. It does it with and without the quadzilla plugged in and ive had a few different injectors in it in the past year and all have done the same thing including the stock injectors so i dont think that could be the problem. Could it be the APPS? Anyone have any ideas? Thanks in advance guys anything might help me out. The truck is a 99, 5spd, it has an airdog 150, CAI, quadzilla ADR 4k, 7x14 sac injectors, hx52,

Ok... I'm going to ask for a bit more information...Fuel Pressure? Do you have a fuel pressure gauge? What is you fuel pressure at idle and at highway speed WOT?Do you you have any error codes?Check in on this and let us know...

Describe the "miss", do you feel it "Jerky,lurchy or surging" or hear it or both? Dead miss or intermittant miss ect any kind of details will help. I have ridden in several rigs where folks thought they had a miss and it wound up being the road cracks transferring sound through the rig. it gets tricky with loud exhaust and drone noise in the cab to differentiate some times. Once you point out the obvious it is one of these :banghead: moments.

Fuel pressure stays at about 23psi at idle and drops to 16-17psi and wot. The only code that has came up is from over spinning the IP and quadzilla said it will do that when it gets close to 4k rpm. It's sounds like the engine will cut right out almost like a bad lope. The truck seems like its going to hop off the ground and the drive train is going to fall out if I let it do it. If I lay into the pedal it will clean up just over 40mph but can still feel it jerk a little bit. I know this sounds like might be lugging it to low but I don't think it's that.

--- Update to the previous post...

Alrighty well I tried a new APPS and coolant temp sensor today and neither one changed anything. I had my one of my buddies hook his snap-on scanner up to it these are the codes that came up on it. 00594? sayes it isn't documented? And I got these P0251, P0237, P0217, and P1691

And I got these P0251, P0237, P0217, and P1691

VP44 is shot...

P0251 - VP44 Pump Fuel Valve Feedback Circuit - Death Code

http://articles.mopar1973man.com/2nd-generation-24v-dodge-cummins/59-obdii-error-codes/169-p0251-vp44-pump-fuel-valve-feedback-circuit

P0237 - Map Sensor Low

http://articles.mopar1973man.com/2nd-generation-24v-dodge-cummins/59-obdii-error-codes/167-p0237-map-sensor-voltage-too-low

P0217 - Engine Overheat

http://articles.mopar1973man.com/2nd-generation-24v-dodge-cummins/59-obdii-error-codes/162-p0217-engine-overheat-condition

P1691 - VP44 calibration error - Death Code

http://articles.mopar1973man.com/2nd-generation-24v-dodge-cummins/59-obdii-error-codes/230-p1691-vp44-controller-calibration-error

Sorry...

Those codes are most likely from when my IP took a dump like 3 years I have never had a good scanner hooked up to it until today to erase them. Could this be?

Ok... Even at that length of time the error should of self erased by 3 years... The PCM and ECM will self erase codes after 40 warm up cycles of the engine.

Warm-Up Cycles

Once the MIL has been extinguished by the Good Trip Counter, the PCM automatically switches to a Warm-Up Cycle Counter that can be viewed on the DRB III. Warm-Up Cycles are used to erase DTCs and Freeze Frames. Forty Warm-Up cycles must occur in order for the PCM to self-erase a DTC and Freeze Frame. A Warm-Up Cycle is defined as follows:

[*] Engine coolant temperature must start below and rise above 160° F

[*] Engine coolant temperature must rise by 40° F

[*] No further faults occur

So I figure in a month or two the old codes should been long gone if the truck was driven everyday. So now that you dumped the codes now take a ride for 5-10 miles and check the codes again.

Alrighty thanks a lot I'll have to try that tomorrow.

--- Update to the previous post...

Ok I scanned it again today and got these codes back. P0251 and 00594 but I still don't know what that one means? And a P1693?

http://forum.mopar1973man.com/threads/2573-P0251-Fuel-Inj-Pump-Mech-Failure-Fuel-Valve-Feedback-Circuit No listing for 0594. 1693 is a companion code, just telling you there are codes present. How did you read your codes?

Hmmm so probably a bad VP then? My buddy has a big snap-on scanner

Yea, time for a new VP. Sorry. There are a couple of vendors here that sell VP's. Good luck.

Alrighty thanks a lot for the help

jason, check this thread out member has it for sale http://forum.mopar1973man.com/threads/5152-SO-VP44-for-sale-and-used-150-hp-BD-injectors

0594 is the cruise control system, servo-control, circuit open, code.This is a generic code for all manufacturers.