Still have the p1131 issue

[joshwfl]

Comes on every time it's cleared within about 20 miles of driving. I have so far:
-Cleaned the MAF, no difference
-Unplugged the MAF, it climbs RPM slower, but I haven't driven with it unplugged
-Checked all visible vacuum lines, no leaks
-Checked for CAI leaks
-Checked for intake leaks by spraying around it, no idle change

The car still runs good, no stumble or miss, but it seems like it should have more power.

I thought about just replacing the MAF, but I don't want to throw a $100 part at it that can't be returned.
Any other ideas?

 

[trombonedemon]

P1131 Lack of Upstream Heated Oxygen Sensor Switch - Sensor Indicates Lean - Bank No. 1
Things to check for include high fuel pressure, low fuel pressure, restricted fuel filter, engnine misfire, leaking intake manifold gasket, incorrect (stuck open or too cold) engine thermostat, low engine coolant level, restricted air filter, leaking vacuum hoses, or anything else that could affect fuel mixture. If the vehicle has a lot of miles on it, you may want to try replacing teh oxygen sensor, they ened to be replaced for amaintenance at around 100000 miles anyway.

 

[joshwfl]

P1131 Lack of Upstream Heated Oxygen Sensor Switch - Sensor Indicates Lean - Bank No. 1
Things to check for include high fuel pressure, low fuel pressure, restricted fuel filter, engnine misfire, leaking intake manifold gasket, incorrect (stuck open or too cold) engine thermostat, low engine coolant level, restricted air filter, leaking vacuum hoses, or anything else that could affect fuel mixture. If the vehicle has a lot of miles on it, you may want to try replacing teh oxygen sensor, they ened to be replaced for amaintenance at around 100000 miles anyway.

Fuel filter is new, no misfire, not sure of the t-stat temp, but the gauge always shows proper heat up time and is with correct range. No change in RPM when spraying carb cleaner around the base of the intake, coolant is topped, K&N is clean, vacuum all checked out visually and by spraying,. Guess I'll move on to the O2, I do have 130k on the clock.

What should the car do when the MAF is unplugged?

 

[trombonedemon]

http://www.stangnet.com/mustang-forums/603723-maf-unplugged-torque-y-ride-plugged-slow.html When you move to the O2 sensors, check for freyed or exposed wires.