Hard start after fueling and loosing fuel pressure after sitting

[Chevyfein]

I can hear the fuel pump turn on without engine running. I notice that after my drive home from work about 20-25 minutes when I pull into the driveway and throw it in park it starts to have a weird idle kinda bobbing up and down but idles fine else where ? 

[richard wysong]

Welcome to the Forum! Some vehicle info would be helpful, year,engine,model etc. How do you know it loses FP when it sits? Have you tried cleaning the throttle body and IAC if it has 1?

[newdude]

4 hours ago, Chevyfein said:

I can hear the fuel pump turn on without engine running. I notice that after my drive home from work about 20-25 minutes when I pull into the driveway and throw it in park it starts to have a weird idle kinda bobbing up and down but idles fine else where ? 

 

 

Year, make and model of truck?

 

Sounds like a bad purge valve based on your hard start after fueling the vehicle and stumbling idle but you need to test your fuel pressure first with a fuel pressure gauge to make sure the pump is working fine.  

 

Edited October 30, 2024 by newdude