Just recently acquired this truck from my cousin who to say it nicely "neglected" this truck.

codes thrown are p171 and p174 lean on bank 1 and 2

anway the problem started out as a vacuum leak which I thought I had fixed. a couple weeks go by and the the engine started to idle very rough but at constant rpm of 700. while driving it would be fine until around 40mph violent shaking and misfire cel would flash until my speed decreased. my first thought was cop or plugs , but the next day it got worse and stalled at red light and when backing out of driveway.

I also notice signs of oil spray under the hood on driver side near the EGR valve.

I also went to clean the MAF and inside of the intake wwas very dark almost orange colored oil of some kind.

Also pulled the pcv valve and every thing seemed ok

I'm currently checking egr system
and connections

If anyone knows what will fix it would be greatly appreciated.

 

The oil in the MAF is probably blow-by coming from the crankcase and fouling the sensor. Check the PCV hose closely. The rubber elbows oftensget soft and crack over time causing a vacuum leak as well. Replace the PCV valve if it has close to 100k miles on it. This is the factory recommended interval.