my car has check engine light on. It was on a few years ago, turned out to be a gasket problem in the gas tank. It was fixed then. But it is on again and I do not know what could be wrong this time.
“I do not know what could be wrong this time”
From a distance, neither do we!
Take the car to Auto Zone, Advance Auto, O’Reilly, Napa, or another auto parts retailer that does free scans of the car’s OBD system. Only by scanning and obtaining stored trouble codes can anyone tell you which one of hundreds of possible problems might be indicated by the CEL.
After you get the code(s), come back to this same thread and post them. One or more of the forum members will be able to give you some specific guidance once the code(s) are a known quantity.
That CEL (check engine light) is just a kid in class waving her hand trying to get you attention because she has the answer. You need to have the codes read. Some places will read them for FREE. Try Autozone or Advanced Auto Parts. Get the exact code (like P1234) not just their translation into English and post it back here.
Regarding warning lights:
if the coolant temp light comes on, shut off the engine ASAP
if the oil warning light comes on, shut off the engine ASAP
if a FLASHING MIL/CEL comes on, shut off the engine ASAP
ASAP means driving to the berm of the highway right now and not waiting for the next exit.
But if the MIL/CEL is not flashing, then it’s not an urgent indicator.