p1416 code
my 2002 did it last year.
https://ls1tech.com/forums/general-m...lve-where.html
replace both, cost around $11 each.
GP sorenson valve, duralast #E204, oem #779-2929
current autozone part number = 555050, "air pump check valve"
might be able to find them cheap on rockauto also.
I would have to look at the full diagnostic for the air pump system and the relevant codes, but to my knowledge it's fairly common a p1415 or a p1416 code by itself is a good indication it is an air check valve. If the air pump itself was not working I think there's a different code for that, plus both O2's would not see a leaner condition and you should see both p1415 and p1416.
I just re-read the original post, "also throwing codes for running lean on both banks".
I only saw P1416 posted, so if it's just that then i'd be fairly confident it's just a check valve especially for a '99. But if you have other codes being thrown then obviously you may have other problems, need to post those in order to diagnose properly along with any other work and mods done.


