Newly Purchased '99 Silverado 5.3 4wd w/ DTC Questions

[shoey]

Hey everyone, I'm new to the forum and GM vehicles! Yesterday I picked up a '99 Silverado 1500 with 165k miles and I ran my scanner today and found a handful of codes:

 

P0141 - Oxy Sensor Heater Circ (bank1, Sensor2)

P0154 - Oxy Sensor Circ No Activity Detected (bank2 Sensor 2)

P0155 - Heated Oxy Sensor Heater Circ (bank2, Sensor 2)

P0171 - Sys too Lean (bank 1)

P0174 - Sys too Lean (bank 2)

P0405 - Exhaust Gas Recirculation SensorA Circ Lo

 

In the drive home after buying, the truck seemed to drive as I would expect and get up and go without hesitation; no odd sounds or vibrations, seems like a very smooth engine. I was semi-surprised that it idled at 500 RPM which is lower than the vehicles I'm used to.

 

From my limited engine knowledge it would appear the 02 sensor codes likely are playing into the lean environment codes. From what I've read, seems like a lot of people look into fuel pressure and checking the vacuum. What would you all recommend I do to begin fixing these?

 

Thanks for the help!

 

From what I've read, seems like a lot of people look into fuel pressure and checking the vacuum.

[anumber1]

The O2 sensor codes are for the sensors after the cats, both sides. Probably not the lean condition but dead sensors/broken wiring/disconnected sensors.

 

I would suspect it needs intake gaskets (they all do eventually).

 

The EGR valve may need cleaning/replacement.

 

Just an internet guess but I would imagine it needs a through going over.