Question Asked: Rough idle but otherwise runs fantastic
November 05, 2009, 02:21 PM
Truck runs great when driving down the road and idles smooth for a couple minutes after coming to a stop. Then it develops a "stumble" that is very pronounced. I'm fairly confident it isn't ignition as the distributor, cap, plugs, wires, and coil are new. Grounds that I can find under the hood check good. O2 sensor is new. TPS is new and and at .6v at idle. MAP sensor is new. Spraying starting fluid around the intake doesn't reveal any vaccum leaks. Throttle body is clean. Fuel pressure is good. EGR ports are clean, but I'm unsure how to check and make sure it seals closed.
Other than at idle truck runs great and gets 17+ MPG on the interstate. What have I missed?