Rough idle 1996 Chev.PU 350 Vortec
Truck has 250k miles, I put the last 100k on it ,changed oil every 3000 mi and it has always ran fine.After I retired it set for 2 months ,before I started using it again.Since then it has had a rough lopping idle. Starts right up and drives out fine ,but rough idle.No codes on readers. Any ideas please.