I have a 89 Ranger 2.3L with the distiberless ignition. I has what seems to be a dead miss at an idle but goes away when above 1200rpm. Replaced plugs and wires, ran KOER test and returned code number 11 which is systems pass. Coil packs check good and are firing good blue spark.
Tps checks good. Fuel pressure good. Idle air selonoid good. Map/BP sensor good.No visble or audible vacuum leaks. Replaced the fuel injectors. Ran compression check and good there. EGR valve checks good and the EGR sensor checks good.
The only thing that I have found bad is the electronic vacuum regulator that supplies the EGR with the vacuum is bad,but when vacuum to the EGR is applied with a manual vacuum pump,there is no change at all in engine performance or idle.
Any help would be greatly appreciated.