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CRC MAFS cleaner

To clean the MAFS, buy a bottle of "CRC Mass Air Flow Sensor" cleaner, available at many auto parts stores. Just hose it down, but don't touch the filaments with anything (such as a Q-tip). It's in a red and white spray can.

In order to take off the MAFS, it's often recommended you first disconnect the battery [see Tech info for more on this].

Then, you'll need a "safety Torx" bit in a size I forget--these have a little hole in them as the MAFS has tiny "pins" in the middle to keep hooligans (or non-Ford service techs!) from messin' with it. You also have to disconnect the sensor from the wiring harness (pretty obvious how to do that). If you remove the sensor, be very gentle when you pull it out; it is not something you want to handle indelicately.

Or, you can remove the air intake tube (as I do) and sensor in one piece and "shoot the cleaner down the tube".

I just hose the metal filaments down until the cleaner is literally pouring onto the floor. There are several angles you should hit it from, including from the underside.

Give it plenty of time to dry, then replace. **Note: do not "shake it dry!"


Ouila! Cleaned sensor. Gently push it back into its housing, tighten the screws down until they're snug, connect the harness, and reconnect battery.



Hope this helps.

--Scott
 

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You can look at O2 sensor output at idle and instantly tell a vacuum leak, there will be no crossover at the switching point of .5 volt. BTDT on 2 Foci and 1 F150. Ford used really crappy vac hoses that bubblegum up and then the side sucks in to make for leaks. Very common problem. On Focus it's the PCV entry way down at back bottom of intake.
 

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Problem Solved

Within an hour, the local mechanic down the street at MIDAS :)was able to determine that the cause of my problem was a vacuum leak, located beneath the Throttle Body Intake tube, (spoken about in this forum before..the one that kinks).

It is apparently a port that is on both the SOHC and the DOHC TBI, But, the orfice is CAPPED in the DOHC. The port is used on the SOHC model. The cap had somehow freed itself, and was causing this leak.

I don't think that I would have ever found this, I am so happy now.

Oh well, I spent some extra money on O2 sensors that wasn't required, but at least the problem is fixed. The diagnostics and repair was $49.95.
I was so happy that I had them replace all of the worn out tires with new Bridgestones.

I will try to grab a pic of the port that I am referring to, and maybe help others in the future.
It w
I'll probably be tackling this same problem this weekend along with replacing the VSS. Thanks for the info.
My daughter owns a 2000 Focus ZX3, and I have replaced so many parts as well (Spark Plugs, Spark Plug Wires, EGR, Coil, Fuel Filter, Air Filter) and seems to still stall when RPMs get low for turning, or when at a stop. Will need to try and replace the PCV Valve and Hose next, but definitely will need to check for a leak. I did notice that the hose going into the air filter canister is lose and the canister itself has a small corner crack. Could this be the cause of the issue? This past weekend i finally replaced the fuel and air filter, after i had already replaced everything else. And my daughter drove it all day on saturday without any stalling or dying, then yesterday she calls me and tells me that as she was getting ready to go to work, it started stalling again as it did before i replaced all parts.
 
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