Ok, '98 Caravan, 3.3l, 105K Miles.

Will start and drive but runs very poor at low rpm. Will not idle. When coming to lights you can keep in running by holding throttle partially open while on brake. Runs good at highway speed. Acceleretes relatively smooth. Rev in nuetral it will smooth out around 2K RPM. Not only stalls but misfires badly until 2K RPM.

Things checked:

Appears EGR is operating OK. I can see the valve move in and out when RPMs change.
New fuel filter installed.
New idle control valve installed.
Throttle body removed and carbon cleaned.

I don't think it is related but this got bad when running E-85. Switched back to Gasoline without any change. Stalled some before E-85.

Thanks for the help.

 

In those flex-fuel vehicles, isn't there some sort of sensor in the fuel line? Maybe that is going bad. Also, E85 is corrosive, maybe you need to replace some fuel lines, could have a small leak somewhere screwing with fuel pressure.