Hello all, just wanted to let you all know that I have had problems with my Chevy express van 199284 miles in the past. Check engine light on. I went to Auto Zone and they told me the error code was P0300. I read multiple posts about people replacing costly parts and not solving the problem. Just wanted to share what has worked for me. I'm not an auto mechanic but I am pretty handy. Replaced spark plugs and spark plug wires. No change. Emptied gas tank and added fresh gas. Also replaced gas cap. Engine check light went away. A year later, same thing but could not get it to clear. Went to Auto Zone again. Same P0300 code but they said it was valve cover gasket. Read another post and they recommended to clean maf sensor with maf cleaner spray. Removed assembly and cleaned. Also cleaned air filter(not really dirty)with compressed air. Restarted and drove a couple miles and check engine light went out. So far so good. Thanks to all who have posted. Hope this helps.