Ran one tank ethanol and light is on.Anybody know to turn light off?Seemed to have slightly more power but mileage was lousy.2002 Supercrew Lariat 5.4

 

You need to get the codes read. Go to an auto parts store such as autozone and they will read and clear the codes for free. Then come back here and ask for help with the code or do a little searching. It may be nothing to do with you running ethanol.

 

I got the codes read and it says running lean.Any ideas?

 

Do you have 1 code or both? po0171 and po0174 are the lean codes and it will make a difference if its 1 or both.
The pcm is trying to lean out the engine to compensate for a rich condition. It could be a fuel component issue or an air leak problem.

 

Was the '02 even rated to run ethanol? (And by Ethanol, I assume you mean E-85, not the 10% corn-gas Sunoco sells)

-Joe

 

Why did you run ethanol?

I wonder if the exhaust fumes from it destroyed your 02 sensors in front of your cats. Might want to check them out. If your 02 sensors in front are malfunctioning it will cause your vehicle to run rich or lean.

You can clear the codes by disconnecting your battery for a few minutes and tapping on the brake to clear out any built up juice in your system. Then reconnect the battery and the codes will be cleared. If they come back then the problem is still there.

 

Reset your codes. Pull the neg battery terminal for a minute or so and don't do it again.

FYI this is one of the answers to a FAQ on E85

5. Q. What happens if I accidentally fuel my gasoline powered vehicle with E85?
A. Although your vehicle was not manufactured to run on E85, no problems should occur if you mistakenly fuel once with the alternative fuel. The largest difference between an E85-powered vehicle and a gasoline-powered vehicle is computer modules meant to read different amounts of oxygen within the fuel. E85 contains a higher amount of oxygen than gasoline and E85- compatible vehicles are made to read that higher amount. When a higher amount of oxygen is read by a gasoline-powered vehicle, your "check engine light" may appear. Therefore, a one- time use of E85 will not hurt your engine, but long term use could damage your vehicle.

JMC

 

Absolutly correct.
Further, extra oxygen bearing fuels in a normal gasolene engine will make it run lean because the amount of this fuel needs to be increased nearly 2 times in volume to be at correct air/fuel ratio which is not the same a/f ratio number as gasolene.
The PCM is not program caibrated for it's use nor is the hardware capable and the Ox sensors are not calibrated for that fuel so will react with a trouble indication that would be a normal result.
In addition, the PCM has shifted it's tables trying to account for a problem it can't correct.
Imagine if you never got a CEL light and kept running this fuel, what the results might be later on!
Rebooting the PCM to get it's tables back to stock center setting is the best way to go in this case otherwise it will take some time for the tables to go back within there normal ranges and possibly clear the CEL by it'self if at all.
If the PCM is not rebooted the engine may run very rich (on gasolene) and generate a DTC just from that alone. So you can see problems both ways to cause confusion about on what is going on.
Using other additives in volume and frequency can shift the program tables in much the same manner, cause plug deposits etc, -- don't use them.