Random Missfire Code

[jasper3]

I recently purchased a 2006 Colorado 5cyl and it is setting code p0300. I had heard of cylinder head concerns for these trucks which can set this code. I had checked the compression and all cylinders were within 15lbs of each other so I wasn't overly concerned about a serious engine problem. It had codes p0300 & p0305 in memory when I purchased it but did find the spark plugs were worn and hoped this was the reason. The p0305 did not return after the spark plug install. The odd thing is the p0300 code will only set when engine idles for more than 5 mins, never while driving. It does seem slightly rough at idle in park, but not knowing these engines I can't say it is excessive. The engine performance on the road is very good with no power loss. I am hoping there may be something else that may be common to set this code besides the valve spring/seat problem. I work at a Volkswagen dealer so I can read codes and do basic OBD2 checks but have little ability for diagnostics. Any help would be appreciated. Thanks! Oh and any Volkswagen questions are welcomed.

[Stevens03]

Dirty MAF sensor will trip a p0300 code. Guys who run "oiled" filters tend to over oil them when cleaning and the oil gets to the MAF sensor tripping the SES light. Cleaning it can help alot. Also, I'd look at new wires too. There could be a bad one.