'99 Silverado 5.3l Po171-po174 Codes

[TooTall1]

My '99 Silverado 5.3L is throwing both PO171 and PO174 codes,but only in cold weather.We had a few above freezing days and the Check Engine light went off,but as soon as it got cold again it came back on,checked the codes and it showed PO171 bank 1 lean and PO174 bank 2 lean.Any ideas?

[MarkD]

I just solved this problem by installing a new intake gasket, using a MAF aerosol cleaner, and changing my fuel filter. The gasket actually solved the problem.

[Sierra54]

Same here. Last month I put in a new intake gasket and fuel filter. I tried cleaning & replacing the maf but that wasn't it. It wasn't horribly difficult to replace the gasket, I just followed the steps in the repair manual. However, the tube to erg valve was difficult to re-attach properly as it's not very flexible.