Check engine light came on after filling with.

LET'S START WITH THE CHECK ENGINE LIGHT

IT CAN BE ON FOR MANY (HUNDRED OR MORE) REASONS

SOME ARE NOT SERIOUS---OTHERS ARE

GET IT CODED----YOU MAY HAVE A SENSOR NOT WORKING

WE GOT TWO "LOOPS"---"OPEN" AND "CLOSED". WHEN COMPUTER CAR OPERATION IS DISCUSSED

"OPEN LOOP" MEANS THE SENSORS ARE GIVING THE COMPUTER "REAL TIME" INFO, EXAMPLE: O2 SENSOR IS TELLING THE COMPUTER THE OXYGEN CONTENT IN THE EXHAUST SO IT CAN ADJUST THE INJECTORS TO GET THE MOST EFFICIENT "BURN" POSSIBLE.I RECKON YOU COULD SAY THE PRESENT ENVIRONMENT IS CONVEYED TO THE COMPUTER SO IT CAN MAKE INSTANT DECISIONS TO MAKE THE VEHICLE RUN AS EFFICIENTLY AS IT CAN

BEING THAT IT TAKES A 'BIT OF TIME' FOR THE O2 TO WARM UP TO "TRANSMIT" INFO, MAYBE SOME OF THE OTHER SENSORS TAKE A LITTLE TIME TOO. OR IF A SENSOR "GOES OFF-LINE". HOW DOES THE ENGINE RUN DURING THIS "BLANK INFORMATION" PERIOD OF TIME. THIS IS CALLED "CLOSED LOOP"----THIS COULD BE CALLED "DEFAULT MODE" FOR THE COMPUTER TO OUT-PUT INFORMATION FOR THE ENGINE TO RUN

THE ENGINE RUNS "CLOSED LOOP"---WHICH MEANS THE COMPUTER HAS "PRESET" VALUES PROGRAMMED INTO IT--IT RUNS OFF OF THEM, UNTIL ALL SENSORS COME ON-LINE. CLOSED LOOP SORTA MEANS THE ENGINE IS "FED FALSE INFO", THAT WILL MAKE THE ENGINE RUN---THIS "LOOP" IS NOT EFFICIENT, USUALLY YOU WILL NOTICE IT RUNS RICH--AND MPGs GOES DOWN!

THIS IS NOT ONLY TRUE FOR THE O2 SENSORS, BUT OTHER SENSORS NOT WORKING WILL CAUSE THIS (STAYING IN CLOSED LOOP)---CLOSED LOOP IS BASICALLY "DEFAULT"

I'M NOT GREAT ON NEWER VEHICLES, IMMA JEEP CJ KINDA GUY '40-'86 IS WHAT I KNOW THE BEST. BEFORE COMPUTERS!

MANY POPULAR AUTO PARTS STORES WILL "CODE YOU" FOR FREE

WRITE DOWN THE #s--THEY WILL BE IN A FORMAT SORTA LIKE "P0345" OR ANOTHER "MADE UP" EXAMPLE IS "PO445"

JUST 'CAUSE THE "AUTO PARTS STORE MAN" SAYS, "IT'S YOUR EGR"----HE MAY BE WRONG---YOU NEED THE EXACT CODE #. YOU MAY HAVE TO ASK HIM FOR IT, IF HE JUST SLINGS OUT A DIAGNOSIS

TAKE THE EXACT NUMBER TO "GOOGLE"----TYPE IN

"OBD-CODES. COM/ P0?" (INSERT WHATEVER YOUR CODES ARE---YOU MAY HAVE SEVERAL---DO THEM ONE AT A TIME ON YOUR GOOGLE SEARCH)

NORMALLY YOU WILL WIND UP ON A PAGE THAT EXPLAINS WHAT THE CODE IS/ WHAT HAS HAPPENED/ WHAT YOU MAY BE EXPERIENCING ---AND MAY GIVE YOU "POSSIBLE CAUSES" AND "POSSIBLE SOLUTIONS"

RETURN HERE WITH GOOD NEWS THAT YOU HAVE IT ALL FIGGERED OUT. OR WE'LL SEE IF WE CAN ASSIST YOU MORE

THE MEDIC