Yeah,the first one I bought like that was a Ď00 model VIN 5 truck. Guy threw all kinds of parts at it,and then came to the conclusion it needed an ECM,then sold it to me off of Craigslist. It had spark,fuel,crank signal monitor from a scan tool,and compression...2 of the cylinders where lower then the other two,..like 110,70,110,70..or something like that. Your compression,and which cylinders are effected is going to depend on how many teeth off,and if any internal damage occurred.
I pulled the cover,and it was obvious after that. The crank was at TDC,and the camshaft was 3 teeth off...not to mention the chain was loose,and the tensioner fell out when I took the cover off..with the notch in the crank timing sprocket pointing up,I removed the chain,and backed the camshaft sprocket up to correctly align it to the mark on the camshaft sprocket,and replaced the tensioner with a $10 autozone part..put the cover,and snout back on with some RTV,and cranked the truck..it fired right up,and ran perfect,so I took it back apart,and replaced the oil orafice,timing sprockets,chain,timing cover gasket,and front seal with GM parts.hat engine has been in 3 different trucks since then.