Sounds like you may have dirty or bad lifters and low oil pressure, you can try adding Marvel Mystery Oil to your engine oil to clean out the oil journals. If your lucky, it's going to be just dirt in your lifters and at worst. Your going to have to replace the lifters. Start with the Marvel Mystery Oil which you can get at Auto Zone and if your having problem locating a bottle, you can get away with ATF. ATF is a high detergent oil that will do the same but Marvel mystery I find is better on cleaning out the internal parts in the engine. You can leave it in there till the next oil change and you may even notice the ticking noise to get quieter or disappear totally. Good luck and keep me posted and what size engine is your Sonoma?? 4.3 V6??? or the 2.2 L
