2011 Sierra Issues

[madeintexas1975]

2011 Sierra-5.3, flex fuel, active fuel management.....
Truck is slow to start. Not dragging, but turns over more than normal. Starts fine when cold or has sat for several hours. Seems to only do this after engine has warmed. Also, is it normal for oil pressure to fluctuate wildly? Seems to drop off when engine idling and picks up when I accelerate..

 

[Heard]

Your oil pressure is going to go up when you accelerate. The engine components are going faster which in turn will make more pressure inside it. My guess for the reason the truck turning over faster when starting when its hot is that the oil is warmer and not as thick as it would be when its cooler. Live in Canada so when starting the truck here in winter you can tell when the oil is cold by how the truck turns over in the mornings, especially when it hasnt been plugged in.

 

[GMC Customer Service]

2011 Sierra-5.3, flex fuel, active fuel management.....
Truck is slow to start. Not dragging, but turns over more than normal. Starts fine when cold or has sat for several hours. Seems to only do this after engine has warmed. Also, is it normal for oil pressure to fluctuate wildly? Seems to drop off when engine idling and picks up when I accelerate..

madeintexas1975,
Have you had a chance to take your Sierra into your dealer to have them look into this for you? They may be in the best position to get your concerns diagnosed for you. Please keep me posted and if you have any questions, comments or concerns please feel free to contact me anytime.
Thank you,
Stacy GMC Customer Service