I've searched and can't seem to find this particular issue. A week or so ago I noticed the engine had a slight "edge" to it; it wasn't as smooth as usual. Then the Check Engine Soon light came on when my wife was driving it. I checked the gas cap (start cheap, right?) but that didn't help. Checked oil which was fine. The number 3 on the coil pack had the pitting that seems to happen frequently so I changed the coil pack, wires, and plugs. I reset the computer and all was well. Today, the light came back on after the engine warmed up. I went into a store and was there long enough for the engine to cool and the light went off until the engine warmed again.

Any thoughts on what could cause this? I will probably have to get the loaner scanner but thought I'd start with this knowledge base.

 

Till you have a code fromthe scanner, anything is just a WAG......

 

Yeah...you really need to just buy or borrow a code scanner. Some can be had for as cheap as like $40...way cheaper than just changing random parts.

Btw when I bought my car the CEL came on after a 1,000 miles. I tightened the gas cap and reset the code because it was a very small leak evap code...and it went away for 4,000 more miles. Reset return in a few miles...when I inspected the gas cap this is what I saw...the seal around cap is cracked every 1/2". New gas cap ordered from Bavarian auto...no return of CEL for a few months now.

 

As Zippy said, it could be anything. But one common problem seems to be the knock sensor. If you try putting in a top tier gasoline for a little while you might get lucky.