Code po300?

Almboss · January 25, 2016

So my story goes like this:

Drove my truck over to a friend's house on Sat night. The truck sat for 4-5 hours. Got in and started it up and drove off. Didn't notice any misfires or stumbling. Got on to the highway and was at normal cruising speeds and looked down and saw the check engine light flashing. The truck felt under powered as if in limp mode but it would maintain 65mph. Then the light stopped flashing but the truck would not go into v4 mode at all and 6th gear was stubborn to shift into. Just parked the truck when I got home.

The next day checked the scanner and the code po300 came up in the history, but not as active. Took the truck for a drive around town, it drove fine went into v4 and I belive 6th gear ( was city driving and wasn't counting gears as I drove).

Trying to figure out why it threw a code. Only think I have done to the truck is cut the muffler off. Just got it first oil change done at the dealer last week.

Anyone experience anything similar to this? Should I just take it in to the dealer and see what they say? Or am I wasting my time with that.

redwngr · January 25, 2016

P0300 is 'random misfire'.

oldscsc · January 25, 2016

Take it to the dealer if it's under warranty. There is freeze frame data the dealer can access and use to aid diagnosis.

Also, a flashing check engine light means that the PCM has detected a misfire severe enough to potentially damage the catalysts. If the misfire continues, it could lead to an expensive catalyst repair down the road. The more documentation you have that the root cause began under warranty, the better off you will be.