Heya;

Wife just reported this, so just starting to dive into it. Driving the truck, when there is any load on the engine, the AC will not work, however when in idle it will work fine. Immediately think of either low freon or faulty condenser core, what do you guys think?

 

Does it stop working, or do the vents just switch to the defrost?

 

After I asked her again.. she said its coming out the vents.. sounds like a wild vent ehh?

 

Yep. You must have a pretty serious vacuum leak somewhere if it only works correctly at idle.

 

I'd agree... before today, she said it only did that on hard acceleration, then she heard a noise today and now does it all of the time except at idle.

 

Check the plenum thread stickied at the top of this forum. There is also a thread on wild vents, and the fixes, in the FAQ section. (along with service manuals you can download. ) With that kind of mileage, timing chain and gears wouldn't hurt you either.

 

Kegger mod, timing set, water pump, ECT tune, plugs, wires, cap rotor - it will run better than when it was new! All that for a couple hundred bucks! OK. Maybe a little more than a couple....

 

I had already bought the new cap / rotor, plugs and wires (I like to change these everytime I get a vehicle). Just haven't put them in. Also looks like its leaking in the differential from the plug, so I'll probably change the fluid in that as well and clean out the vent. I wouldn't be shocked if this truck served as a tow vehicle in a past life. Drives great though right now.

 

There is a TSB on routing plug wires. It seems to make a difference and eliminates crossfiring or misfires. In the FAQ/DIY section.

 

Follow up to this thread as well.

Fixed this problem, it was the Check Valve, not the one at the manifold, but instead the one at the T section. Replaced the old film can with a new nickel sized one, and also had to cut off an inch of vacuum line because it was brittle and broken. But all is well as far as that goes. Again the Part # for the Check Valve is 4549209, and got it at a dealer for $4.60.