Fuel economy, idle, emissions problem -- please help

[Josh Kinsley]

Thanks for the reply, Probedude.

The exhaust hose to the BPT is clear. I *did* remove a
restrictor that was in the tube between the BPT and the EGR
valves, thinking that the small hole in the restrictor might
be plugged.

When I say the EGR twitches but doesn't stay up, I mean when
I rev the engine from idle to ~5000 RPM, I feel small
erratic movements, but no sustained change in position.

All symptoms, including poor fuel economy, are still
present. I changed the O2 sensor about a year ago, and just
recently verified that it is still switching regularly.

MAF grounding -- good thought. I regrounded my MAF per the
SE-R.net procedure years ago, but haven't checked it since.
I'll take a look, although I'll be amazed if that turns out
to be the culprit.

Thanks!
Josh

Probedude wrote:

> Well, I would have said you need to check your
> base idle but you did that
> correctly from your description. Check and clean
> your AAC valve (controls
> idle speed), it may be sticky.

<snip>

> You say the EGR doesn't stay up.  Are you testing
> this at about 2200 RPM?  Can you tell if the exhaust
> hose to the BPT isn't clogged.  You mentioned you
> cleaned it, but is it clear all the way?
> About the fuel economy, is the poor economy
> before you changed the O2 sensor?
> Lastly, have you checked your MAF grounding?