I have noticed that my truck has been blowing a bit off blue at idle. I have 231000 km and drive it maybe once a month now. What could be wrong?

Anyone?

Vootoo thats how mine started last fall and just got worse all winter and spring until it smokes all the time now.( unless the dealers looking at it) ;)
I would save up for injectors or trade before it gets too bad if I was you.

The Canadian injector policy is 7 years or 320,000 km which is 200,000 miles if you do the math. You will have to check your in service date to be sure. Do a search on this site to get the actual TSB. Hope this helps.

I had the same thing happen. GM refused to honor the warranty. The problem was overfueling of #8 injector. GM said it did not fall into the waranty coverage. I had to pay to have the injector replaced. Had all 4 done on that side. Warranty on those is 12000 miles or 12 months.

Most likely the injectors but you wont know until you put a scanner on it to check the injectors