Little Bit of easy Maintenance for the 15 Suburban

[GreyStone]

I am trying to gain back some lost MPG, noticed over the year, same driving but now 2mpg less
100k miles currently on the odo
also running rich at startup/idle (truck stinks big time, I have other modern v8 around, none smell like this)

not quite severe duty, but lots of Idling in the AZ Heat

I am planning on changing the following, these are relatively inexpensive parts, I can change myself, have you guys done any of these on your 15 and later

-Spark Plugs (just done recently, OEM parts)

-first I'll do 2 can of intake cleaner, hopefully cleaning up any carbon buildup a bit
-4 new oxygen sensors
- new mass sensor
-new air filter (these are changed on time)
see below
Truck is stock, no xmas tree lights on

anyone changed the above and got better drivebility/ symptoms I have above resolved?


thanks!

see below

 

[GreyStone]

remember some areas have summer and winter blends - sometimes one blend or another will affect mileage.

 

[AZCreeker]

I think the chance that the O2 sensors AND the MAS AND the ECM fail at the same time are so extremely remote, it is implausible. Generally, if there is a failure in the fuel management system, it goes full rich to prevent detonation, but you mention no CEL. Are you sure it works? Try to get the codes read to see if there is anything. The plugs / coils may be a place to look, but without any CEL, the other stuff is just throwing money at it.

I got a LS engine specialist indies shop change the plugs and look at the coils.
I dont have a CEL, my main issues is really freaking rich at startup no matter hot or cold.
then once I start driving and then idle no more stickiness.
I compared the smell compared to my friend 17 escalade and even a friend ram 1500 hemi 19 and its like 100 times as stinky.

 

[Brother Bluto]

Does your CEL light when you start the truck? When the key is turned to accessories, but before start? This confirms it does light