Cm870 random stumble

[Rawze]

(04-27-2022 )Precisionw900 Wrote:  

(04-27-2022 )Rawze Wrote:  It can be a whole lot of things.. including even the head and/or valve train itself wearing out.

Inspecting the overhead cams, doing an overhead valve adjustment, etc. is one place to look too.

Thanks Rawze. 398k miles and overhead just recently run and everything inspected. Injector leak and cutout test ran within 8k miles but plan on running test again to be sure nothing has changed. New hoses from tank to lift pump and Lift pump doesn’t cavitate but a air leak beyond that is always a possibility.

Another concern or symptom is a shortly after start up the truck will be idling and will jump up 50-75 rpm. and stay there. Is this normal? I recently read on another thread about a engine that would do that and I believe you stated the only reason for that is it’s getting fuel it shouldn’t be and pointed towards metering actuators.

Hopefully I will begin trouble shooting tonight.

yes... you should do the things/tests talked about in this thread...
ref: http://rawze.com/forums/showthread.php?t...4#pid71234