She failed the emissions test because her OBD system did not provide information about the engine's RPM.

The CEL is not on.

This probably has something to do with my ongoing problem expressed in other posts and below: (I'm hoing this new information will narrow down the possible problem even more)

She needs a little throttle to start the engine sometimes. Sometimes she idles weird, but that has been better since replacing the fuel filter.The RPMs will have a hard time recovering when the throttle is let up while driving (approaching a stop sign, for instance,taking the foot of the accelerator will result in the rpms divingdown to 200 and shuddering, and then recovering back to about 1000.)Sometimes she will stall in this instance. Shifting to Neutralwhile letting go of throttleprevents RPM issue described above.

And in general, the MPG are about 33% lower than where they should be, depite a new fuel filter, fuel injection cleaner, etc...

This has been going on for about 4 months now. Thank you for this site.

Rick