deleriumtremor
Well-Known Member
- Thread starter
- #1
Been a while since I checked in here.
Just a heads up for anyone that gets a check engine light (MIL) P0171 shortly after refilling.
We were in Las Vegas and just before heading out to return home, filled up a pretty empty tank at a Chevron station. About 40 miles into the tank full of gas I got a Check Engine Light. I did a quick scan while still driving along and found a P0171 code (engine unable to adjust for a too lean condition). The engine was running fine, no temp issues, etc., so I kept going.
My first thought was maybe I got a bad batch of gas (maybe too much ethanol in the batch). At about 200 miles in I was averaging 15 mpg on freeway miles I should have been seeing over 21+ mpg (hilly but not extreme climbs), so it was clearly dumping as much fuel into the intake as it could to compensate for the lean condition. I did a live data look at the other EFI engine parameters and everything seemed fine. The upstream O2 sensor was switching fine, so my guess was an induction leak, clogged injector or some bad gas.
At St George we had about a half tank, so my thought was to fill up with some Premium Ethanol Free gas and see if things settled down a little mileage wise. The app I used to get to a station that was Ethanol free just got me to a regular Texaco station with normal E10, so I filled up with their Premium and called it good. It took about 100 miles before the mileage started creeping back up and by the time I was in Salt Lake I was seeing about 19.5 MPG average, so was convinced I had gotten a batch of gas with too much Ethanol in Las Vegas. We ate lunch in Salt Lake and I filled up again with some normal E10 91 octane Shell Premium and reset the code with my cheapo scan tool.
As we went along mileage continued to climb and when we arrived home in Idaho, I was getting 23.5MPG and the P0171 code never returned. My guess is my original hunch was likely correct and the bad gas was the culprit. Oh and when I checked, I had about 4 messages from Ford that I needed to get my truck into the dealer asap, one of the messages was from the front camera that had gotten blocked with snow and so my collision warning was suspended, along with the MIL from the lean condition. Ah modern technology....
Just a heads up for anyone that gets a check engine light (MIL) P0171 shortly after refilling.
We were in Las Vegas and just before heading out to return home, filled up a pretty empty tank at a Chevron station. About 40 miles into the tank full of gas I got a Check Engine Light. I did a quick scan while still driving along and found a P0171 code (engine unable to adjust for a too lean condition). The engine was running fine, no temp issues, etc., so I kept going.
My first thought was maybe I got a bad batch of gas (maybe too much ethanol in the batch). At about 200 miles in I was averaging 15 mpg on freeway miles I should have been seeing over 21+ mpg (hilly but not extreme climbs), so it was clearly dumping as much fuel into the intake as it could to compensate for the lean condition. I did a live data look at the other EFI engine parameters and everything seemed fine. The upstream O2 sensor was switching fine, so my guess was an induction leak, clogged injector or some bad gas.
At St George we had about a half tank, so my thought was to fill up with some Premium Ethanol Free gas and see if things settled down a little mileage wise. The app I used to get to a station that was Ethanol free just got me to a regular Texaco station with normal E10, so I filled up with their Premium and called it good. It took about 100 miles before the mileage started creeping back up and by the time I was in Salt Lake I was seeing about 19.5 MPG average, so was convinced I had gotten a batch of gas with too much Ethanol in Las Vegas. We ate lunch in Salt Lake and I filled up again with some normal E10 91 octane Shell Premium and reset the code with my cheapo scan tool.
As we went along mileage continued to climb and when we arrived home in Idaho, I was getting 23.5MPG and the P0171 code never returned. My guess is my original hunch was likely correct and the bad gas was the culprit. Oh and when I checked, I had about 4 messages from Ford that I needed to get my truck into the dealer asap, one of the messages was from the front camera that had gotten blocked with snow and so my collision warning was suspended, along with the MIL from the lean condition. Ah modern technology....
Sponsored
