2009 mazda 3 starts, idles, but will barely rev up
 

My 2009 mazda 3 today will start and idle fine, when I press the gas it barely revs up and has no power at all. Check engine light is on but I have no way to pull the codes. All I can really do with it is move it on my driveway. I hadn't driven it for a week or so before this.

Any ideas before I call someone to come get the car?

a little more information
 

The car has done this once before, 6 weeks or so ago, I turned off the car, restarted it and it was fine. I could never get it to happen again so I couldn't get the code read.

It accelerates enough to get the car moving if I near to floor the gas pedal. It's as if 90% of the gas pedal does nothing. It feels like it's running OK, but it's hard to tell. My exhaust is still clear, no blue exhaust, but the exhaust does smell of gas. On the other hand I've never smelled the exhaust before this so maybe the smell is normal.

OK, today the car feels like running properly
 

So I took a trip down to autozone to pull the codes. One code is saying it doesn't like the new fuel cap I bought. (P0441) Another code is saying my APP (Accelerator pedal position) sensor is bad. That tracks seeing as how the engine is running fine, it just doesn't seem to know when to accelerate any more.

So my question to you guys, the sensor is pretty expensive ($350 or so). Does anyone know if the sensor is part of the gas pedal assembly? Maybe my answer for right now is to try to get one from the junk yard as it's a fairly rare problem.

Any advice would be appreciated. My first pass at google only netted me one short conversation (Accelerator Pedal Position sensor (APP) - code P2122 - Mazda3 Forums : The #1 Mazda 3 Forum) about the problem and no parts hits. Thanks

Have your MAF sensor checked.