Low RPM and Surge

[TDSECK]

I have an intermittent problem of when I am in reverse the 6.5 sometimes surges at slow back up idle . Does any one have any ideas what would cause this?
It has been doing this for about a year.

More recently I notice at idle the RPM is a bit lower than is was. 600 vs 700 and off idle response is poor till it reaches 1000 rpm.
My first guess is the lifter pump, and or fuel filter..
And other things I should look at after I check those two?

[john8662]

That's an odd one, the surge at backup. I have a customer here locally that complains of this. I haven't gotten to troubleshoot it yet.

But..

I suspect it's an air problem in the system, or a restriction.

J

[DmaxMaverick]

Many "direction specific" issues can be associated with the condition of engine and drivetrain mounts. Forward and reverse will torque/twist the drivetrain in opposite directions, and worn out or broken mounts can allow harnesses/connectors to be pulled or chafed, which may also apply to fuel supply lines and mechanical connections.