Checking a few things
 

Just want to make sure the car is behaving normally, so here is a list of things I notice.

Shifter vibrates quite a bit.
Idle is not entirely smooth; occasionaly it sounds like one of the ignition cycles does not occur (misfire).
Car will idle at about 800 RPM until I put the car into gear when at which point it shoots up to about 1100.
When the car first begins to idle it sits at about 1100, which will drop to about 800 when I turn the wheel or start the AC.
There is a wierd metal flapping noise when I get on the boost occasionally in second gear.

That's about all I can think of as far as wierd engine things goes. Do you think some of this might be cause by a leaking FPR? The flapping noise I believe I have read about somewhere. Not sure about the wierd idle problems.

Thanks guys!

I think you'd smell gas from a leaking FPR before you see degraded operation... But I could be wrong. As far as the odd idle behavior in and out of gear goes, and with the A/C on/off... Try replacing the clutch switch. I believe there is also some sort of electrical load circuit someone had mentioned before... Not sure though..

Fuel pressure regulator only gets activated during hot start, according to the manual.

How are your motor mounts? I ask because my shifter danced like a hula girl when mine were broken (driver's side, actually).

The "putt" at idle is pretty typical from what I've read and seen.

The idle seems pretty normal. Wheel turn or A/C will load the engine which drops the rpms, though on my car, the idle speed control will compensate for this via the ECU controlling it.

The shoot up when placing in first is not normal, though, which is to say my car doesn't do it :)

The rattle I don't know about. My car rattles and buzzes all over the place, usually on the passenger side at the firewall. I chalk it up to demonic posession, but maybe that's just my provincial nature...

I know my FPR is going. I've been told it is leaking, although I really don't smell any gas under the hood.

So things to check. Idle speed control, a mysterious "load circuit ;)" and the clutch switch.

Motor mounts may be bad. I'll be getting under the car in a week to change my front sway bar mountings, so I'll know then.

The metalic flapping niose is usually the heat shield covering the lower passenger side of the firewall. I bent mine a little and put a couple rubber washers at each bolt to raise it off of the body.
My car Idles similarly to yours. When my car sits for a minute the idle drops to 800 rpm's otherwise it's around 1000 - 1100 rpms. The idle should fluctuate when you turn on the a/c or turn the wheel. However, I'm not sure that my idle is correct either. Also, I don't know about the fact that your car shoots up to 1100 when you put it in gear. That seems strange.

One more thing. When in gear and I'm pushing the throttle down and up (backing up) the engine will run a little rough when I let the pedal come back up. I'm starting to think some of this might be dirty injectors, but I blame everything on them :)

It's your fuel pressure regulator. I had a lot of the same symptoms. Mine was just leaking fuel straight into the intake manifold. The second I replaced it, my idle became much smoother with less "backfiring". It also stopped doing the rev to 1100 rpm crap.

You will want to fix it soon. Mine was leaking bad enough that the extra fuel was actually lowering my compression -- by washing the oil away. The second my mechanic closed off the tube to the intake manifold, my compression went up a couple of inches.....

This, like any other fuel-related problem, is a must fix now. A new FPR lists for like $160 from Mazda, you can get it cheaper from Malloy or Mazdaformance.

rynberg, I was thinking of doing the FPD at the same time. I don't know if you have any experience with the FPD, and I know mine is not currently doing anything it's not supposed to, but should I change it as well?

FYI

FPR
$100.80

FPD
$93.00

I believe it's a bit more work to get to the FPD. I didn't replace mine.

Ray told me those fail regularly. He stocks 12 as opposed to 2 FPRs.

This is an automatic, isn't it....

If this was the lounge I would have had an appropriate image for your post. No, it is not an auto.

Haha, sorry, i just skimmed the posts and didn't see mention of "clutch switch"...I was thinking that since the idle goes up when you put it in gear, that i could see it being more likely on an auto. Very strang on a manual though. No input from me though, sorry.
~Tom