Have a 1999 3.0 V6 that runs well, but has an uneven idle. I replaced one lazy O2 sensor, replaced sparkplugs, cleaned the EGR and MAF. There are no codes, however, the timing jumps between 22 to 26 degrees at idle. The long term fuel trim on bank 1 is 0.7%, while bank 2 is 3.1%. Vacuum hoses appear to be OK. Have also added injector cleaner 3 times. Just bought the truck. Any suggestions would be appreciated. Wish I had a better scantool.

 

Fords have been know to idle a little ruff, is it really bad?

 

Its not too bad, but it annoys me and I have never seen the timing vary like it does.

 

Try some Seafoam and then replace plugs and fuel fliter