[Hotrod25]

My check engine light came on about a week ago on my way to work. I drive a Chevy Cavalier. It scared the crap out of me! I pulled over and smelled the car (making sure it wasn't running hot). Yes I have a working temperature gauge but I did not want to take any chances.

I took my car to Advance Auto (no Auto Zone here) ~ the lady tested it and said it was my gas cap. The error read emission leak or something like that! I took off the cap and put it back on. She reset the light. Well 2 days later it came back on.

What the heck? What could it be? Could I need a new gas cap? Could it be a leak? Help!

[Midnight Tech]

Replace the cap, Hotrod - if the light comes back on then have a "smoke test" run on it.

[MaximumSpeed]

Yeah, hope it is just as easy as replacing the cap. If that doesn't fix it, there might be a hole forming at the top of the pipe near the cap. On the other hand, the check engine light comes on for MANY things (including hitting a certain number on the odometer), so it might have come back on for a totally different reason the second time, and you should go have the parts place get a reading again.

[Hotrod25]

I should be able to get a cap at the Auto place store right? I don't have to go to the dealership (I'm hoping). Once I replace it how long should I go before I get it tested again?

What the heck is a smoke test?

[Midnight Tech]

Any auto parts store should have the correct gas cap for your car.
Ever notice a small green cap under the hood with a tag attached? That's the port for the smoke machine. It sends a smoke into the evap system at a set pressure to determine leaks in the system.

[Hotrod25]

You know I did not notice that, but it's smart. So where would I get a smoke test done? At the garage? I'm sure not sending anything through any part of my vehicle looking for a leak. Is it expensive?

I picked up the gas cap yesterday - the guy told me to change it out and see if the light goes off by itself. If not in a few days they will reset and then we will see if it comes back on. I'm not sure why he did not just reset it.

[silverfox]

My father had a car I used to drive alot. He told me that if the engine light comes on, do not worry about it and do not panic and take it to a garage. He had it checked out many times, and there was never anything wrong with it besides the light coming on all the time. Was it faulty wiring or something? We never knew. Go figure.

[Hotrod25]

I have since replaced the gas cap and guess what? The light is still on! It doesn't bother me much except I have to have the car inspected by the end of September.

[MaximumSpeed]

Yeah, I would recommend having the auto parts store recheck it. They do it free, right? One of them told me once that when your car hits so many thousand miles, the light will stay on until a mechanic resets it inside the engine.

[HANG]

That check engine light is ridiculous. The thing comes up when there is nothing wrong but when there is a problem it does nothing.