been chasing a miss / rough idle. Engine is smooth & strong at 1000 rpm or higher. So far have replaced the EGR valve, EGR controller, throttle position sensor and air filter. Check engine light went out, idle is better but still missing while accelerating. So installed new plugs, cap and rotor. Plug wires have about 15K on them. Old plugs look good, no oil fouling. Checked timing with ECS unplugged. Exactly O degrees with 1 to 2 degrees of flutter. Advance looks normal, is steady but went ahead and installed new timing chain set (and water pump). Starts fine but with rough intermittent idle. Idles smoothly at 1000 rpm. Runs good and strong at speed.
Vacuum lines? Water in gas tank? Distributor?