MAF has been cleaned a few times. Mechanic also was able to check it was funtioning properly.

O2 Sensor not changed I believe where exhaust leaked (although both banks are lean now).

I have not had any bogging down.

 

Maybe check Fuel Pressure.

 

Yeah, that was what I was thinking it might be the injectors or a fuel pump. He did notice that on starting up it didn't seem to be very strong to startup. Maybe that's not the right word. What is curious is that the CEL when it shuts off, always comes back on very shortly after starting up, but only after I've accelerated a bit.

 

How often do you drive around with the Fuel level below 1/4 tank.
Driving around below that level puts extra strain on the Fuel pump causing a shorter life.

 

I've noticed for quite some time when its under 1/4 tank, the fuel starts to cut out. So I really never get it under 1/4 tank, haven't for a few years.

Do you think that could be a possible symptom that the fuel pump may be the issue (as I stated earlier I think the CEL seems to come on and off at certain levels of gas in the tank like when the fuel is between 1/4-3/4 full.

 

although when i asked he said the fuel pump if there was a problem, you should feel a change in performance. but maybe its sporadically failing? is that possible at all? plan is to get the freeze frame data and they'll run it at that load and conditions.....

 

The fuller the tank, the easier it is on the pump.
If it's coming on even @ 1/2 tank, yeah it could be fuel pump.
The fuel pump is in the gas tank. Not cheap!

A while back I remember some gas tanks in some Mazda's had issues with spiders in the gas tanks vents. This may be worth exploring .

 

I've never let it get much under 1/4..maybe the first year or two but that's it.

actually the CEL usually shuts off when there's less fuel. LIke before my last fillup, my CEL was off for about 6-7 cycles from about 3/4 tank down to 1/4. But when I filled up with gas, the CEL came on after 1 or 2 cycles later. Its all kind of random when it does this.

maybe the fuel pressure is too high?

 

If it was too high you may get CEL codes of too rich.
You are getting lean codes-----not enough fuel.

 

maybe a fuel filter is blocked/plugged. I was looking at the computer this morning at the exhaust shop. he had a little list of different possibilities and the steps to check it out. Checking the fuel pressure was one of them...he didn't think it was low compression...hopefully not, said it seemed to be running fine aside from it seeming to struggle to start at times. not really struggle, just a bit slow to do so.

Signs & Symptoms of a Clogged Fuel Filter | eHow.com

I swore they changed it out when I got my car serviced at 105k (the CEL came before this service).