A/C problem w/acceleration

Old 09-09-07, 12:01 PM
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A/C problem w/acceleration

1998 Ford Explorer. A/C works great, but on acceleration the a/c blows out the dash as in defrost mode. Let off the accelerator and a second or two later it blows back out the vents. Drive up an incline at any time and it reverts back to defrost mode. It started off slowly at first but now is worse. I recently changed the plugs and wires and now it's even worse (no air out front vents till I let off the accelerator), although I can't find any hoses I dislodged. I think it's just been getting worse over time. Thoughts?

Last edited by mike3699; 09-09-07 at 12:02 PM. Reason: better description of event
Old 09-09-07, 12:20 PM
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Sounds like a vacuum hose leak.

Inspect all your hoses behind the dash and in the engine bay. I also believe there is a hose connected near your A/C evaporator, passender side, upper corner near headlights. It's under some brackets but I've heard these have issues.
Old 09-09-07, 01:11 PM
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I 2nd that. My car did exact same symptoms. Exact. And it was caused by a split in a harder type vacuum tube that forked off the vacuum assist power brake unit, on my particular type car.

My car also had A/C. ( I said "had" because it was removed and never put in again after head gasket and some other engine work.)
Old 09-09-07, 01:32 PM
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check the areas you were working when changing plugs etc. probably a cracked hose or one you knocked off, even slightly, or cracked vacuum fitting, I'm guessing close to the firewall area. I know some vehicles also incorporate a vacuum check valve in the main vaucuum line feeding the controls, to eliminate what your experiencing, that have been known to malfunction.

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