How long would it take a "check engine" light to come back on if that was not the issue?

Question

I have just purchased a 2008 Toyota Sienna. The check engine light just went on with random misfire on 2 and 6. Checked the spark plug. One was a little black so the mechanic cleaned it off a bit with a machine and put it back in. He reset the code to see if the "check engine" would come back on. How long would it take to come back on if that was not the issue?

Answer 1

Hi there

Depending on the severity of the misfire it could come right back on or take a while. If he solved the issue then it's likely not going to come back on for 100 miles or so. If it's a fairly strong or consistent misfire, then the light would come on fairly quickly, usually within 10 miles or so.