Archived >2500 RPM engine surges

[dsanderlin]

Help! >2500 RPM engine surges

New member. After reading recent and archived post, I think my problem is the lift pump. Your comments thoughts??



PROBLEM: Engine surges(like misses) >2500 RPM whether in/out of O/D. No black or white smoke. 99/3500/Auto/106K... stock.



Thanks in advance,

Dave

 

[Alan Reagan]

A common cause of surging/missing like you are describing is a faulty camshaft position sensor (CPS). Another unlikely candidate to cause this is the Accelerator Pedal Position Sensor (APPS). The lift pump can cause this but it would be unusual for this to occur at a specific RPM. That's why I would lean toward the CPS.

 

[Missouri Mule]

How about TPS ( Throttle Postion Sensor) if you still have one on 99's.

 

[BV]

TPPS

I don't really think it's the TPPS (Throttle Pedal Position Sensor). When mine (99 2500) started to go bad it would flat fall on it's face (go to an idle) from hwy speeds and then return to normal.



If you can change throttle position and it goes away then you might look into the TPPS.

 

[Paychk]

What about water or algae in the fuel, maybe a healthy slug of algaecide/fuel conditioner in the tank and drive it around some will help?

 

[Alan Reagan]

Water in the fuel should give you a warning light and algae will usually be felt at all RPM ranges. To check it though, just put you a catch jar under the drain and open the valve. Algae will come out as a slime and water will settle right to the bottom.

 

[dsanderlin]

All, thanks for your quick response. Doesn't appear to be anything elect (ie: tach stable, only happens at WOT & >2500 RPM) I could be wrong though!! Purchased new filter and Lift pump... even if the lift pump is not bad I'll have one on hand as I move across country from VA to ID(bully dog tech here I come).



Solution to Date: New tank of fuel (little better), new filter(today), awaiting fuel gauge kit from Geno's.



Anymore sugestions?



Again... thanks,

Dave

 

[MidwestMotorman]

unhook battery

I recall a trick in another thread on the newer trucks. Disconnect both batteries for a while. Then hook them up, turn on the key, push the accelerator to the floor and let it return back up. Turn off the key, then turn it on again and start the truck. This should reset some parameters and maybe help.



Good luck