What do I do if the engine on my 2011 gmc sierra is running rough?

Question

My gmc sierra truck is registering the code P0300 which I obtained through onstar diagnostics while the truck was running. I have changed the spark plugs already with implementation of ac delco plugs with the 160,000 km range. what would you recommend to try and fix the problem?

Answer 1

HI there

It could be the result of low fuel pressure or intake manifold gasket leaks. With the engine running try spraying some carb cleaner along the intake to see if the idle changes or becomes smoother. If it does, then you have a leak, if not then I would check the fuel pressure.