Please HELP with some diagnostic codes

[vinceseg]

I've been experiencing a bit of rough idle since I've owned my 05 Tahoe (01/12) and then it seems to smooth out. Until this week, and now it stays very rough at idle almost like it's ready to stall and the check engine light came on today.

Got 3 codes...

P0300 - Multiple misfire detected
P0174 - Bank 2 System too lean
P0151 - O2 sensor low voltage Bank2 Sensor1

Do you think this is as simple as the O2 sensor or is that getting thrown because of a different issue?

Thanks,

Vince

 

[markvdb]

You are probably looking at new intake gaskets. My 02 did the same thing. I had the intake plenum replaced, 350, but may have gotten away with just the gaskets. Get the new type.

 

[clkelley]

Just to check for the intake gasket, while it is idling, throw a quick shot of carb cleaner at the base of the intake manifold and see if that effects the idle at all, this will tell you if you have a blown gasket, if so shut it down QUICK as you are probably getting coolant in the oil and you don't want to ruin the bearings.

 

[vinceseg]

I called GMPP on Monday to see what was covered or not and decided to take it to dealer. It was the O2 sensor. Mechanic said normally it also throws P0171 along with 174 when it's the gasket. He did a spray test on intake with brake cleaner (i think).

Running better than it ever has now (fingers crossed). This thing has been a nightmare in the 6 months I've owned it.