Have bought an older expedition with over 300000 miles on it. Has some quirks that I need to get resolved. First is when running ac on max and taking off down the road if I really get on it the air stops coming out of the dash and not sure where it is blowing. As soon as it gets to cruising speed it comes back out of the dash like it is supposed to. I imagine there is a weak vacuum switch somewhere that trips when I get on the gas hard. Other is real bad vibration in truck at cruising speed that is felt in the seat or in truck as a whole. No shake in the steering wheel. Out of balance driveshaft? I have new tires on it and it is 4wd. Have ordered new front cv axles but I would think I would feel it in the steering wheel if that was the real problem. Does not shake when parked and I rev it up. Any ideas?
a few problems
- Thread starter jcressm
- Start date
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stamp11127
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Welcome to the site. Standard vac leak is the hose under the battery. Even though the tires are new you should check them and the rim for roundness. Is the truck lifted and if it is by how much?
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docraymund
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You have a small vacuum leak somewhere thats why it only happens at open throttle when manifold vacuum is lowest. Your driveshaft is out of balance.
AZ59apacheguy
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I was told by a mechanic that that is normal for the a/c to not come through the vents a WOT on this era Ford......
stamp11127
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This recommendation is safe if you stay away from the tires and drive shaft with the engine running & trans in drive.
Place the vehicle on jack stands. With a helper, observe the drive line in operation at different speeds. Do not get under it or near the spinning driveshaft or tires. If you should get caught in it - lets just say you would be "bent out of shape".
You will "see" where the problem is. Take note for a bent driveshaft.
Place the vehicle on jack stands. With a helper, observe the drive line in operation at different speeds. Do not get under it or near the spinning driveshaft or tires. If you should get caught in it - lets just say you would be "bent out of shape".
You will "see" where the problem is. Take note for a bent driveshaft.
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