Engine stumble on startup

[LWDUPPONG]

I'm hoping for some ideas on this one. After starting my truck it will stumble for a split second and then recover. It doesn't do it all of the time. Sometimes it will do it for a couple days and then it will be fine for a while. Somedays it will do it every time I start the truck and others it will only be initial start up in the morning. Temperature (engine or outside) doesn't seem to make a difference. In the last year I have replaced the injectors and installed a FASS 95 pump. No other problems that i have noticed, just this occasional stumble on startup. I'm not setting any codes either. It has never died completely just a stumble. It seemed worse after I installed the FASS but then it cleared up and went back to being an occasional occurrence.

 

[p-Bar]

Could be the FCA , could be an injector leaking down. Could try the 2stroke oil in the fuel tank to see if it is a sticky FCA, probably the cheapest thing to do.

 

[BIGNASTY]

Amalgamated

Could be the FCA , could be an injector leaking down. Could try the 2stroke oil in the fuel tank to see if it is a sticky FCA, probably the cheapest thing to do.

Amalgamated not only lubes but it cleans so there is a reason to add fuel additive

 

[rbattelle]

Intermittent cam or crank position sensor, maybe? Although I'd expect either of those to trip a MIL. Can you put a code reader on it and check for stored codes?

Ryan

 

[LWDUPPONG]

I'll try the 2 stroke oil first. I had a cam sensor go out about 2 years ago and it never set a code until it completely died. I usually run FPPF Total Power or Power Services. All my Peterbilt customers seem to use one or the other.