ill try to make this short as possible. i got a old beater '92 lebaron that i normally drive to work but the clutch went out so now im driving my '96 v6 4x4 dakota. i have several dirtbikes and any extra premix gas that i didnt use after riding i would just put in the car gas tank so it wasnt sitting around the garage. but since the car is broke down i put it in the dakota tank. about 1 gal of premix, and i made sure the dakot tank was full so to dilute the premix as much as possible. anyways it kicked on the check eng light. so i just left the light on and drove the truck for few days until half a tank was gone then refilled it, and drove it for a few more days until it was half a tank again then refilled it, then i unhooked the battery for 30min and hooked it back up. after 30min or so the check eng light came back on. its giving me code 51 which is lean air/fuel mixture by a abnormal rich correction factor.

engine runs fine BTW. but anyways my question is, is the check eng light coming back on because the code is stored in the computer (even though i unplugged the battery for 30min), or is there a sensor still picking up trace amounts of the premix oil ? thnx for any help

 

I've run premix in mine a few times and never had a problem. I have friends who do the same thing and they haven't had any problems, either.

Maybe the O2 sensor(s) got coated with oil and aren't reading right, or maybe the check engine light has nothing to do with the premix.

 

ya i knew it wouldnt cause a problem because ive put premix in other vehicles. just got sick of seeing that check engine light on but wasnt sure if unplugging the battery completely clears the memory but i think it does. i put more regular fuel in the tank and unplugged the battery again today. i think one of the sensors was still picking up trace amounts of oil but all the oil should be pretty much gone now because the light is staying off .