I am a first time poster here and have an issue with my 1999 suburban, 4wd, 5.7L, 153K. The engine light came on the other day after it had been idling a little rough. I went have the code read and the guy said that it was a miss fire on #6 cylinder. Are there any obvious things to check or look for? Is there a common issue that I should check first?

 

Do a web search for trouble code P0306? It basically means cylinder #6 didn't contribute enough to the crankshaft output. Check for the usual suspects such as ignition and fuel injection components, and compression on that cylinder.

 

I know this is gonna sound strange but my 99 Suburban had the exact thing and it turned out to be a leaking intake manifold gasket. apparently the Dex cool antifreeze ate the gaskets out. The problem was fixed with new gaskets and green antifreeze.

 

got that problem after changing/upgrading the intake manifold gaskets it turnout being a stuck poppet valve in the fuel injection spider i did the spider upgrade and cleaned the mass airflow sensor and it runs great now the fuel injection spider upgrade is worth every penny,check for spark and compression


Sean
1997 burb

 

I have been losing coolant as well but no leak visible. So I guess that it is possible but how to tell for sure ?

 

Check around the water pump weep hole. If it's not coming out there, then it is either going into the crankcase or combustion chamber. Neither are good options.

 

I'm going down this road too. Can I ask you what it cost for that work? I was told $800. They do a couple of these every month.

 

If the antifreeze is getting in the oil for very long, then there'll be more to fix than just the gaskets.

 

It's been a while since I had ours done but I do think it was in that $600 range. Course the Dex cool had to be flushed and green anti freeze installed. There is also a significant amount of labor. It deffinately cured the problem though. It would only be a matter of time before it got into the oil.