1988 Century Rough idle?

[jaggy810]

Hello everyone, I have an 88 Century, 2.8 with 40K. At idle it seems to "stumble" intermittantly. I changed the plugs, o2 sensor, PCV Valve and cleaned the idle air valve. I am getting good mpg and have no service engine soon light. Any suggestions?

[Hapynzap]

How bout changing the fuel filter?

[jaggy810]

Just changed the fuel filter, still the same rough idle. Are there any sensors that can go bad and not give a "service engine" light? Would a bad Idle air valve not give a light?

[maxwedge]

Pull the egr valve clean up the pintle, could be not seating causing a rough idle.