I'm working on a 1991 GMC Top Kick with a 366cid. Vin# 1GDL7H1P6Mj504874 and has 138,000 miles. It was tuned up at 135,000 with plugs, cap, wires, coil, rotor and fuel pump. A few weeks ago it started to surge and sometimes die when you come to idle but only a... Login to read more.