6.0 Hard Start After Sitting for 48 hrs

[jofosonc]

170000 miles. After sitting for couple days starts up and idles rough then settles down. Immediately put in D and engine dies. Last time took three times before would stay running. Does smoke some when this is going on. 
No Codes

Replaced fuel pump but no change. 
Once it settles down it runs as good as it ever did. Also, if I crank everyday, no problems. 

[CamGTP]

Have you tried cleaning the MAF sensor and the throttle body yet?

 

A gummed up throttle blade could be a cause for poor starting and rough running in some cases.

[jofosonc]

Have cleaned throttle body and replaced MAF. 

Edited December 5, 2021 by jofosonc

[Shall36]

Try cycling the key off-on-off several times before trying to start. If it fires right up, you have a bad check valve in the fuel system. Normally, the check valve is a part of the fuel pump, but I’m not familiar with this setup.