I Have A 2000 Cummins I Recenly( 3 Weeks Ago ) Put A New Injection Pump And Lift Pump In . My Truck Is Doing The Same Thing Again. It Revs Up And Down Revs Up And Down. Then The Check Engine Light Comes On . The Light Will Go Off After A Couple Times Of Starting It. It Seems To Me That The Injection Pump And Lift Pump Wasn't The Problem To Begin With. Any Advise ?

 

what codes do you have?

 

I Haven't Had A Chance To Shoot Codes Yet. Just Happened Again This Morning

 

Im sure you did, but did you change the fuel filter on the motor? Also there is a filter in the tank. Its a big plastic looking one with fine mesh. Could be restricted. If you have added an inline filter before the lift pump, get rid of the tank filter. Also check for any vacuum leaks and maybe a fuel pressure check with a guage.

 

I took my truck to local diesel shop they checked everything out. My chip was fried thats what was causing the reving problems. Runs great without the chip. They sent the chip back to edge to get fixed, it was warrantied I only had it for 2 months