Mazda Repair: 95 nissan altima stalling, mass air flow sensor, mass air flow

Question
I have a 95 Nissan Altima GXE automatic with 127k miles.  The car is stalling at idle and upon deceleration.  Basically it stalls whenever the rpm's drop too low.  The car will start right back up after every stall.  The check engine light never came on during the stalls.  The check engine light came on after I took it to the shop and two codes came up on the scan: mass air flow sensor and knock sensor.  I changed the MAF and it still stalls.  I don't think the knock sensor would be the culprit.  I also changed the fuel filter and fuel lines but still stalling.  The car cranks up fine in the morning and starts stalling after about 10 - 15 minutes of driving.  I live in florida so there's no cold weather.  Any ideas?  

Answer
If a knock sensor sensing a knock condition pulled the timing out at idle or deceleration it would cause it to stall. However, did you ask them the check the fuel pressure or the spark plugs for evidence of fuel starvation or detonation? Did you check the air filter to make sure it was not plugged or the vacuum lines for signs of a vacuum leak? There is still a lot more to be done before this becomes a mystery problem. It could even be something as simple as a cracked or torn intake air tube between the air meter and the engine. Other things could be a stuck EGR valve or a sticking idle air control valve. These are all things that can be diagnosed without going crazy on labor or parts. Expect to pay $300-$500 to have a qualified shop diagnose this problem and repair it. Never have a shop tell you what is wrong and then try and fix it yourself as the shop is not responsible for it if the repairs if they are found to not fix the problem. Take it to a qualified shop "you can find one in your aria by checking the www.cartalk.com website and using the mechanic locator" and let them fix it for you, it will save you money in the long run.

Regards,


John