How To Upgrade a Mustang MAF

How To Upgrade a Mustang MAF


Upgrading your Mass Air Flow Meter can be one of the easiest and best bang for buck modifications in any vehicle, naturally aspirated or not. Normally when you upgrade your vehicle’s Mass Air Flow ( MAF ) meter, you may require a reprogram or slight adjustment in your vehicle’s tune to compensate for the larger meter.

Because the MAF has a variety of sensors meant to accurately gauge the incoming air charge, proper installation of your larger bore MAF is required. Today we’ll be showing you how to install an upgraded 90mm MAF into a 1999 Ford Mustang Cobra.

The Ford Mustang Cobra is a muscle car that has definitely worn the SVT badge proudly. Our 1999 model is one of the first to include the modular 4.6 DOHC version that has now grown into the popular Coyote engine. In what was maybe a bleeding edge motor at the time, the DOHC 4.6L cranked out 320 hp @ 6000 RPM with 317 ft lbs of torque available at 4700 RPM. This engine is generally considered the grandfather to today’s modular DOHC Ford power plants.

This How To Upgrade a Mustang MAF tutorial can be completed in an afternoon’s worth of work with just a few hand tools. We’ll be removing the stock restrictive MAF part number F6UF-12B579-AA and replacing it with a 90mm Lightning MAF part number 1L3Z-12B579-AA.

If you are using an out of the box tuner or preprogrammed chip service, you must make sure to specify which 90mm MAF you will be running. Other 90mm MAF’s can carry part numbers such as 1L3F-12B579-AB or 1L3F-12B560-BB which can vary depending on the sensor element. More on this later.

To begin our How To Upgrade a Mustang MAF article, unplug your air intake temperature sensor and MAF connections.


Next loosen the throttle body inlet to your 4.6L engine and pull off the accordion air snorkel that connects your MAF to the throttle body. If you are still using the factory air box base, you will need to remove all four bolts and nuts and transfer the entire unit to the new 90mm Lightning MAF.


With your stock MAF removed, take a moment to compare it against the 90mm Lightning MAF you will be installing.


Not only a larger bore MAF as you can plainly see, but there’s far less material that poses as a restriction. More flow more air and more power in your Cobra engine is the result of this add-on modification.


Now tighten down the 4 bolts and nuts that secure the MAF adapter to your air filter, or the factory air base if you have not yet upgraded to an aftermarket intake system.

Reconnect the snorkel to your mass air flow adapter and don’t forget to reconnect your air intake temperature sensor as well. You do not need to disconnect the battery for this installation, although it certainly doesn’t hurt.


Make sure to note the orientation of flow as indicated by the arrows on your 90mm Lightning MAF. Once you have all the connections resecured and tightened, you can slide the intake tract back into your engine bay.

Tighten down all the worm clamps on your engine and intake system, and plug in the MAF and AIT and you have now completed our How To Upgrade a Mustang MAF guide.