I've got a 2008 Silverado 5.3L (FFV & AFM) it has been throwing a P0175 and P0172 codes for a few months now, "bank1/bank2 system too rich" I have determined my tune is not causing the code but it does make it come on more often, the tune is the only performance mod on the truck so far. and last night while "racing" down the interstate the MIL light started flashing, (yes I know what that means) so I took it easy the rest of the way home and as soon as I got home I scanned the codes and it said 6 codes, but it was just P0172 and P0175 showing up 3times each,

Also it obvious its running rich, I polished my chrome exhaust tip last week and its already black again, and I'm talking about on the outside of the tip not the inside
Thanks for any help, info, or suggestions

 

Almost sounds like possibly stuck open injectors or maybe even weak spark... Have you by chance pulled plugs to see what they look like, at very least it could tell you which cylinder it is. Can you see the misfire datastream in the ecm? That would definitely help narrow it down you shouldve had a history code for either p0300 or p030x with light flashing.

 

If it were a stuck injector wouldn't the truck idle rough and maybe also run rough at lower speeds? also I feel like it would come on more often if it were an injector, with the tuner on the truck it comes on like every other day, with the tune removed it only comes on like once or twice a week. I haven't yet looked at the plugs, and I have a pretty basic scan tool, I can see some info but its basically just a code reader, I can't look at charts and stuff.
I got the truck earlier this year with 114K miles, it now has 125K miles, the previous owner was my grandpa (he just bought a 2015) and I think he did a tune-up at about 80 or 90K

 

What kind of tuner are you using?? Weak or sticking injector ive seen do it, but typically has some sort of miss associated whther it throws a code or not, need see what MAF is kicking out along with Intake air temp and engine coolant temp, low ect could cause it to enrich the air fuel mix

 

I do actually keep an eye on IAT and ECT, IAT is typically 10-20F degrees warmer than ambient air temp and ECT usually stays around 190-199F
right now I just got a HyperTech Max energy programmer, eventually I plan to get a good custom tune.

 

Can you see your map readings, youve got something goin on with both banks, dont know what i was thinking with the injector thing be very unlikely to have one injector on both banks go out..... Be helpful if you could see data, would help pinpoint your problem.... Have you checked fuel pressure by chance, too much would cause rich condition.

 

OBD-II Trouble Code: P0172 System Too Rich (Bank 1)
OBD-II Trouble Code: P0175 System Too Rich (Bank 2)

Most likely a MAF issue. Especially if you have a CAI or a K&N oiled type air filter.

If the vehicle is Flex Fuel, The ethanol content may need to be reset with a Scan tool.

There are other less likely things it could be as well but you need a proper Scan tool to read the data.

 

Read somewhere there maybe tsb on it for reflash for ethanol content was gonna look for it at work as my exes burban is doin same thing....

 

I had the same issue on my truck.

There was an updated calibration for my 06. My Vehicle already had the update.

I kept resetting the Ethanol content but the codes kept coming back. When I received the vehicle, it was missing the Air filter and the upper lid had a crack in it near the mounting bolt. I replaced the upper lid, installed a new filter, and I tried cleaning the MAF with no change, I had a spare MAF so I swapped it out as a last ditch effort.

The Flex fuel on these vehicles use 02 sensor feedback to determine the ethanol content whereas the older ones used an expensive sensor. If the computer thinks it's getting more Air than it actually is, it dumps extra fuel in the cylinders. The O2's read that and think it's running rich. On a flex fuel vehicle, it will think the ethanol content is higher than it actually is and try to compensate for it.

 

No I dont have CAI (yet) but I do think its the MAF also I think just b4 the code started coming on I took my MAF out and cleaned it, but I've unplugged the MAF so it would have to relay on other sensors and soo far no codes, I'm gonna leave it uplugged for a day or so and see if it comes one, my list of upgrades included a JET performance MAF, so that might just be the next thing I do