i have a 97 GMC Jimmy 4WD 4 door and everytime i use the ac and im at a high rpm, it sounds like a fan kicks on and i loose power and my ac cuts off the regular vents and goes to the defroster dash vents. The power loss even occurs when im not running the ac but it sucks my power out of my truck and sounds like a fan is running at full blast. i have heard vacuum problems but im not sure. I love my truck and these issues are killing me.

second is i need to know if a set of 31X10.50R15 tires(specifcally a set of Uniroyal Liberators or Goodyear Wrangler Authoritys) will fit on my truck with the stock height. It it the SLE model and stock tires are 235/75R15. will they fit or rub?

 

it sounds like youre losing vacuum to the hvac control under hard acceleration. are the vacuum hoses good and is the resevoir still hook up?

I suspect the power loss you feel (And sound) is the clutch fan kicking in as it should be.

Is this different than before?

 

Havent checked it out yet but even whrn the ac is off i loose power.......it pisses me off becausr it wrecks my gas mileage as well.....help!

 

What are the weather conditions around you? If the truck is hot the clutch fan needs to be kicking in. BUT - It could also be locked up.. Gotta check it.

Good luck!

 

In phx, az........lol. says it all. But i shouldnt be losing power like that should i? Is there a way to get rid of it for good?

 

Yes the resevoir is still hooked up. Not sure what shape the vacuum hoses are in but they affected.my truck before when one was off of the resevoir(truck ran like **** and stalled twice but that was a few years ago) she runs cherry now(new distributor and cap, plugs, wires, and ignition rotor) but the ac problem is really pissing me off.......