Hello,

I have a 2006 Mazda3 for about 2 years, recently, the CEL is on and off, not blinking, for many times. For example, it's on for 2 or 3 days and after start up, the light goes off and for another 10 days it's on again. In winter it happend more often, but in summer the light is always off. I check the CEL code is P0171, there is 4 possibilities for this code, (1) dirty/defective MAF sensor, (2) large vacuum leak, (3) fuel pressure low, (4) engine mechanical condition. I changed MAF sensor for a new one at meineke, and the tech double check the everything, but found nothing. Anyone has an idea about this problem? Thanks a lot!

--Bob

 

i've been told before by a shop in my hometown that they can do a "smoke test" where they hook a machine up to your car, and basically pump a smoke-like vapor kind of solution to see if they find any leaks or cracks anywhere.

from the suggested fixes, it sounds like your car's trying to say you might have a leak where you shouldnt. idk tho, just a thought

 

Do you have any other issues other than the CEL? Rough idle, etc.?

It's also possible you have damage to the wires going to the MAF harness. The harness is anchored to the battery box, so it's possible for the wires to get stretched (at the MAF) when the engine moves during use. With the engine running try manipulating the wires in the MAF plug to see if you can reproduce the issue.

 

I was wondering if you ever found out the problem or had it fixed. My 2004 3 s is having the same problem.