Mass Air Flow Sensor 08/05/23 ---------------------------------------------------------------------- I have two vehicles, one is 17 years old, the other is 23 years old. I've always driven older cars, and I try to work on them myself, when the repair is something I can tackle--when it's not, the car is usually ready to get rid of. The 2000 Chevy Impala has been running a little rough, and yesterday morning it sputter out and died in the driveway. Real rough start, on and off idling rough. My wife was very concerned, but I reassured her that such a symptom isn't necessarily that big of a thing. Did a little googling, and a bad Mass Air Flow Sensor (MAF) had identical symptoms. I cracked the hood and removed the part; in this vehicle, it's actually a very simple part to remove, without any need to take apart the intake; two small bolts, and it slides out. Didn't look that bad to me, but it's electrical and looks can be deceiving. Our favorite wiki provides insights as to how the sensor works: "The theory of operation of the hot wire mass airflow sensor is similar to that of the hot wire anemometer (which determines air velocity). This is achieved by heating a wire suspended in the engine’s air stream, like a toaster wire, by applying a constant voltage over the wire. The wire's electrical resistance increases as the wire’s temperature increases, which varies the electrical current flowing through the circuit, according to Ohm's law. When air flows past the wire, the wire cools, decreasing its resistance, which in turn allows more current to flow through the circuit, since the supply voltage is a constant. As more current flows, the wire’s temperature increases until the resistance reaches equilibrium again. The current increase or decrease is proportional to the mass of air flowing past the wire. The integrated electronic circuit converts the proportional measurement into a proportional voltage which is sent to the ECU."[1] Some MAFs have four or more "hot wires" in an array. Mine had only two. They looked OK, but I decided to replace the part anyway, as it was only ~$20 on Amazon. Of course, I needed to see what the local parts stores had first... Autozone had one in stock, but they wanted $128 for it. Silly, when you look at the thing. O'Reilly's would have to order one, and they wanted $84. My goodness... I probably would have paid $49 for it, just to keep the local shops open, but $84-$128? And as for parts quality, I've have excellent luck buying parts on Amazon over the years, so the argument is tough. Oh well; I bought a new air filter from O'Reilly's (Fram, $20--on Amazon you can get an off-brand one for <$10, but a Fram on there is $17), to keep the local shops running, and went home. The part from Amazon said it would arrive next-day. Fine, it is ordered and should be here today. But with some time to kill, I decided to just clean out the old one with alcohol, just for kicks. It looked a little better when I was done. Threw it all back together, reset the computer with a little ODB2 reader, and fired it up. The engine ran great, better than it has in months. No codes (it was throwing P0102 instantly before, after a reset). Drove it around, and it was working great. This morning, just for fun, I also opened up the 2006 Dodge Grand Caravan, to see about the intake there. No MAF, just an air temp sensor, which I cleaned for fun. Long story short: a little bit of dust on a tiny hot wire sensor can impact its resistance and make your car run like crap. A stalling out car doesn't mean the engine is dead, or that you need hundreds or thousands of dollars in repairs--sometimes it just means you need to clean something. [1] gopher://gopherpedia.com:70/0/Mass flow sensor