check for spark at # 3 plug, and take a compression on # 3 and one of the other cylinder and compared it. shouldnt be less then 20% different. finally check for fuel on #3 is that a single injector? might have a bad injector on #3 cylinder.
RepairPal Certified shops can diagnose and repair your 1997 Chevrolet Astro. They provide transparent pricing with a minimum 12-month or 12,000-mile warranty on repairs and services.