I have a 2007 RX-8 GT with manual transmission. 21,000kms on the engine.

The idle has started becoming erratic and stalling. The engine struggles to get past idle and when it does it takes a long time for it to get above 3-4K rpm and if it makes it that far it seems to be mostly fine.

It has a p0171 lean bank 1 code. It was rough running and then it cleared itself up for a few days and the check engine light went out. It was running good for Mazda when I brought it in (of course haha). Now it is worse then before and seems to be staying.

Here's what I have done so far.

Hooked an evap smoke machine to the brake booster vacuum line. No leaks found in the intake.

Sprayed carb cleaner and brake cleaner on the instake and no change was noticed.

Took the MAF sensor out to see if it was dirty. It wasn't, but I cleaned it anyways.

Tried reseting ECU and problem is still there.

If I unplug the MAF sensor the car goes to a limp mode but runs almost like normal. I replaced the MAF sensor with a mazda MAF sensor and the problem is still there.

I am not sure what else to look at other then checking the wiring and the computer at this point. It is still under warranty so it is going back to mazda on Monday again, but any help now would be greatly appreciated.

 

did you swap your air filter or intake? remove the screens in the intake? anything like that...? some 8's don't like it as weird as that seems. What all have you done to the car, upgrades....

 

do you have after market intake?

Check your plugs, one could be loose or broken.

last clogged cat, but those symptoms are usually different.

 

If you have the stock intake on then try cleaning out your MAF.

 

Someone is not paying attention in class.

 

Check your plugs, the white plastic part on one of them could be cracked. I experienced near enough the same thing and found that one of my leading plugs was cracked and burned!

 

The car is bone stock from when I got it. But by bone stock I mean it already had the mazda speed intake and the mazda speed single muffler exhaust.

The final verdict was this:

Mazda tech "suspected" an intake leak but could not find one. they replaced the upper intake and it was better they said but still not quite right. They then changed the front O2 sensor and its been great since. Warranty covered, I was just frustrated that I could not figure it out on my own time.

 

that was the first sign of my fuel pump going bad.. 171

it took almost a year for it to happen..

beers