C1500 idles good til warm up then dies sputtering and missing
Start with basics, like tune up items, check or replace, Spark plugs & wires, cap & rotor, look/listen for vacuum leaks. Look for bad fuses, bad electrical connections. Shorts. Dirty or bad sensors, Throttle body or IAC or MAF/MAP dirty or bad. Throttle body base gasket. ect
So far I've changed. Plugs wires cap rotor coil, upper and lower intake gaskets, spider assembly,upper plenum,fuel pressure regulator, and tons of sensors(cam,crank,knock,ect,iac,tps,maf,map,iat,egr ). Fuel pressure is good, leak down good. At this point I'm thinking timing chain? Codes from the diagnostic(just done cause no check engine light shows) were cam and crank out of range, and cam crank correlation problem.
And timing/cam gears may be worn and if full kit is purchased it will have both. Also check for if they were loose before removing them or if bolts are not torqued down you may need new bolts too cause of stretched threads if it was loose.