2009 Chevrolet 1500 - CO leak

towed a vintage camper from mass to oregon this past winter. now my truck is having very serious carbon monoxide problems… so had it looked at, found to have an oil leak, 2 qts down and when diagnosed now one o2 censor reads high another o2 censor is stuck. what is the correlation? is their a problem with fuel temp / or not enough o2 or was transmission cooler being to hot on huge mts… causing all this ?

Oil leaks and carbon monoxide are 2 different things . If you really have an exhuast leak then get to a muffler shop with all of your windows down . You don’t want to get sick from that and yes I know just how sick you can be from that .

I think you need a shop to actually look at this truck and tell you just what is really wrong.


The 5.3 liter in that generation was pretty bad to burn oil. Search “AFM oil consumption”. GM introduced active fuel management in 2007 on the 5.3’s and had quite a few issues with it. That might be the reason for the oil loss. Burning oil can foul 02 sensors, too.

So you towed a heavy load all the way across the country with your 2009 Chevy truck, and now you’ve done an emissions test and now it shows too much CO in the exhaust?

Are there any other symptoms other than the emissions test? Why did you have an emissions test done?

If I understand your post correctly, my first guess is your cat needs replacement. The cat is what removes excess CO from the exhaust stream. That could explain the O2 sensor readings too. You probably have high concentrations of HC and nitrogen compounds in the exhaust too. The O2 sensors are what the truck’s computer uses to monitor the performance of the cat.

That depends on what “vintage camping trailer” means, could be a 500 pound tent trailer , or a 5000 pound self contained trailer.
But no,

Cold gasoline in the winter would not do any harm .

No, ‘thinner” air (low O2) at high mountain passes would not any harm.

I have towed 1500 pound boat&trailer above 6000 ft altitude with a 318 Plymouth, no problem
Have towed a 26 foot camping trailer above 7000 ft altitude with a Dodge D150/318, no problem.