Aspire idle rough

[Creepin71]

95 aspire 247.000 miles with auto trans idles rough with out load or with load ,just tuned up ,cause car was running very rich as in plugs coated in soot ,plugs autolite 64,cap rotor wires ,filters,found code 17 ,so replaced o2 sensor ,cleared code ,oil change,trans service new filter & fluid,car idles fine once in a while then starts back to rough idle ,but it runs good going down the road ,good acceleration too,any ideas on what to check next ?

[WmWatt]

I'd check ignition components. Do you have a vacuum gauge? It will show misses. My first step would be to clean all ignition components and connections.

[Creepin71]

I had already Checked for vacume leaks hoses manifold gasket etc...

[WmWatt]

^^Not vacuum leaks. A vacuum guage helps diagnose engine problems. Take a look at the permanent thread at the top of this forum page.

[Lives]

My 93 manual festiva is having the same problem. It's been diagnosed as the throttle body and new tb being installed today.

[Creepin71]

Keep us posted .

[ricko1966]

I would pull plug wires one at A time at the cap or check exhaust port temps to see if u have 1 cylinder lying down or random misfires. I am leaning towards temp sender airflow meter throttle position switch issues things that will cause rich conditions. That would explain the rough idle, the sooty, plugs, and good performance with more throttle .