I have a 1991 Ranger it is 4cly automatic belt driven fan. I have replaced plugs, wires, fuel filter, fuel pump, coil pack, had the dis module checked cleaned the K@N air filter. The problem started from time to time now it is doing it 95 to 98% of the time idles at 300 to 400 RPM instead of the normal 600RPM but does not idle rough when you take off it will only climb to 1500RPM and takes forever to get moving. I am pulling my hair out at this point I don't want to keep buying parts that does not fix it I am running out of funds. This motor also has dual plugs and sometimes the tach will flutter kind of a jumpy look but the engine stays at a constant idle. The engine sounds like it's about to die at an idle but doe's not. When it starts idling bad is when the check engine light comes on. Code 88 means loss of dual plug input control and code 18 means Erratic IDM input to processor/SPOUT circiut grounded. I would appreciate any help let me now if I left anything out. Thanks again :bang: :bang: :bang: :bang: