Hey There!

Own a 2000 Ford Ranger XLT (4 cyl). Recently relocated to TX and have been using the A/C a LOT more (obviously). Noticed that when I accelerate, either in town or on the highway, that the flow of air from the vents drops to basically nothing. When the speed is reached and I drop the RPMs the air flow resumes back to normal.

Any ideas? Thanks!

You have a vacuum leak somewhere. The air isn't stopping, it is switching to the defrost only vents. The doors that control where the air goes is vacuum operated with a spring that defaults to defrost. Loss of vaccum results in spring moving the door to defrost default.

It is normal for vacuum to decrease on accelleration. But if it is going away completely, you have a leak.

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(Formerly)
FireRanger
2003 Edge 4.0 4wd

How to: Aux light wiring, relays, & fuses
Info: 300+ intake threads here on FRF
Info: HID Projectors
How To: NO HEAT Troubleshooting Guide

Ok, thanks! Do you know if this an easy fix?

fix = easy
finding the leak = hard

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(SOLD) 2003 Ranger 4.0L V6 FX4
2001 F150 Supercrew Triton V8 (DD)
2008 Fusion 3.0L SEL V6 (my baby)
1992 Taurus SHO MTX (my toy-almost Supercharged)
2004 Nissan Murano SL AWD (Wife's car)

I have had my truck in the shop for 2 straight days looking for my vacume leak. I have my Check Engine Light on with the error code P0171 and P0174 "System too lean". Still cant find it. Good luck buddy!

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2001 Ranger 3.0 V6 Flexfuel 2-wheel drive

The leak is (I'd bet money) behind the intake manifold under the spark plug wires. There are several vac lines back there. They inevitably fail. And when they fail, they inevitably cause P0171 and P0174. And if they fail in a big enough way, they cause your HVAC control to do batty. Spray some ether or starting fluid spray back there. When you hear the engine RPM go up, you hit the leak.

__________________
(Formerly)
FireRanger
2003 Edge 4.0 4wd

How to: Aux light wiring, relays, & fuses
Info: 300+ intake threads here on FRF
Info: HID Projectors
How To: NO HEAT Troubleshooting Guide

Don't mean to hijack the thread.

Check the PCV line. There are rubber elbows that crack and cause those codes. The cracks are hard to see. You have to take the line off and inspect it. Good luck.

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(SOLD) 2003 Ranger 4.0L V6 FX4
2001 F150 Supercrew Triton V8 (DD)
2008 Fusion 3.0L SEL V6 (my baby)
1992 Taurus SHO MTX (my toy-almost Supercharged)
2004 Nissan Murano SL AWD (Wife's car)

Also check the lines running to the vacuum canister. The black "ball" mounted on the pass fender.

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Oh, and what part of Texas did you move to? Just out of curiosity.

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Thanks for your help everyone. I'll check it out and hopefully it'll be obvious in some way.

Sheppard AFB in Wichita Falls.

Ah, welcome to the promised land!

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