Does anyone know how to test the MAF on a 2005 escape 2.5l? I have scoured the net and can't find anything for this model.

i have a p0171 code, and think that it may be the maf. The fuel trim is negative at most speeds.

 

That's a lean code, look for a vacuum leak. Introduce a large vacuum leak, it goes lean. Introduce some propane into the intake, it goes rich.

Shouldn't your fuel trim be going the opposite way or positive for a lean code?

 

I tried spraying propane and starter fluid around and couldnt find anything. The code doesn't always come up right away, sometimes it may last 600 to 1200 miles without a code. It never runs rough, even when the code is on, the throttle response is just a little unresponsive
Thats why I was thinking maf.

 

Use your scan tool to read the MAF value. Actual value will depend on air temperature, density, and flow rate (RPMs). Compare with the standard values in the PC/ED manual.

 

checked the MAF using the scan tool.

At idle 3 g/s and increases as throttle is applied, this seems normal from everything I have read. I guess this eliminates the MAF.

another Idea I have is Maybe the brake booster is leaking air into the system, it is connected to the intake tube downstream of the maf sensor. I guess I could try to cork that off for a week and see what comes about.

just for kicks here is some of the data i recorded at idle
intake pressure 4.5psi
fuel trim idle -4 to 6%
fuel trim long term 12.5%
fuel pressure 38.17 psi
fuel flow .21 GaL / HR
Evap sys pressure -25.75 pa