During cold weather engine code lean bank 1 & 2

[One Trader]

I have a 2003 GMC Yukon XL Denali. I have owned it since it was new and it only has about 55,000 miles. I live in Minnesota so it gets very cold in the winter.

Starting about 3 years ago when the weather would get to around 0 deg F my engine light would come on, but the truck would run just fine. After the weather would warm up to the 30's the engine light would go back off. This has happened for the last several winters although it seems that the light comes on now at slightly higher temps and won't go off until we're in the 40's now.

Now on a recent dip in temperatures to about 0 deg F, the truck starting having a rough idle, seeming like it would die at a stop light, and just not running very well.

I took the truck to the local auto parts store to have the engine code read. They said it was running lean on both bank 1 and bank 2 (same code as last winter as well). However, this wasn't really enough information for me to determine what needs fixing.

I guessing this might be a common problem since a friend also with a Suburban is having the same problem too. Anyone with knowledge in this area able to help point me in the right direction as what needs to be fixed?

Any help would be greatly appreciated.

[Autlaw]

I bought my Yukon used and it ran great for the first year. The second winter we started having the same problems.
I replaced the o2 sensors and it ran better but then said the mass air flow sensor was out of paramators. I cleaned that and it didn't change a thing. Replaced it and engine ran better but not great. Didn't like to idle and acted like it would die at stop lights. Then got a code saying my catalytic was out of paramaters. I replaced them and it has run like a top for the last week. I am hoping this winter we don't see the same problems start up.

[One Trader]

Autlaw,

Thanks for the reply. I did solve my problem though quite awhile ago.

The problem with my truck turned out to be leaking intake manifold gaskets. It's been a couple of years now, but I believe the details were that air would leak past the intake manifold gasket inconsistently which would cause the O2 sensors to change the fuel mixture erratically as well. This was the cause of the engine light and the rough idling.

I have been told that this is a common problem with this year of Suburban. Good luck with your truck.

One Trader