Check engine light on 1998 Chevrolet Malibu LS

After filling the gas tank yesterday, as I was on my way to work, the check engine light came on. Please keep in mind I live in Vegas, and, for the last couple of days the temperatures outside have reached 118 degrees. I have checked the oil and coolant and have resealed the gas cap as well, yet the light still remains. The research I have done leads me to believe the problem may be the catalytic converter, but I’m wondering if there is any further troubleshooting I can do without heading to a mechanic.

Head to AutoZone or Advance and get them to read the code and post back with the code.

Did you tighten the gas cap well? On most cars you have to truly click it three times to make sure it is sealing correctly. Not doing so can throw a code and turn the light on. Loosen and retighten it, making sure it clicks several times. It may very well go away by itself. I’d look there first, since it happened right after a fill up.
If it doesn’t, stop by a pepboys, autozone, advance auto, ect and have them read the trouble code. They’ll read your code for free but don’t buy anything from them but report back here with that code. (it will look like PXXXX with XXXX being a number)

So sorry everyone! I had forgotten to post my results! Evidently during the hot summer here, the petrol vapors have a tendency to affect the seal on the gas cap! It was a simple case of clicking the gascap as you spoke of, and also evidently searching for a better quality gas.


Thanks for the update!

You might want to think about buying a brand new cap. It’s pretty old

As for better quality gas . . . no more Arco, I presume?

I haven’t personally had any check engine lights caused by Arco fuel, but I’m not a fan

Ethanol content in the gasoline mix can affect this. Ethanol vaporizes easily in hot weather, and can cause pressure to build up, that wouldn’t as much if there was less or no ethanol in the fuel mixture. Maybe ask each station you use what the ethanol content of the gas is.

Gasoline must meet RVP (Reid Vapor Pressure) standard of no more than 7.8 PSI regardless of ethanol blend…But with air temperatures of 118 degrees, all bets are off…

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 P0123) not just their translation into English and post it back here.