P0300 code

Thank you. I have warranty on the car as I just bought it 10 back from a car dealer. I am planning to get this checked out and will post back results soon for everyone else knowledge.

Thank you again for the quick response.

Working on my sister vehicle I noticed the check engine light was on. Replaced air filter, and spark plugs (autolite copper core)
got a reading of p0300 at checkers auto part store. What do I need to start looking for. From easy to difficult replacement.

Explorer runs fine, did not feel any misfire, hesitation o slugishnes. My sister said that the check engine light has been on for over 6 months, the abs light is also on.

P0300 is random/multiple cylinder misfire.
There are several possible causes. I would first start by asking how many miles are on the truck and how long it's been since the last tune up. The spark plugs very well may have been the culprit if they've never been changed. And I always recommend using OE or better plugs. Autolite makes a great product, but I would switch to their double platinum plug or the OE Motorcraft for longest life and best performance.
Also, did you clear the code after you changed the plugs? If not, I would do so either with a code reader (BEST) or by disconnecting the battery for a few minutes. If the light comes back on, have the codes pulled again. If we still have the same code, we then need to determine if the misfire problem isis due to lack of spark or a fuel delivery issue.