Vaccuum under the air filter box runs even when the key isnt in

You can have one of several issues that can't be determined without a fault code reader to narrow it down. Typically, it sounds like you have a fuel supply related issue, but it could easily be something else like an unplugged vaccuum line, or faulty EGR. It is best you buy an inexpensive fault code reader and a Haynes Manual for your car... look up the codes in the chapter on Emission Controls and get back with us for assistance. A vacuum line diagram is located under the hood, go over every lie carefully and look for cracks and leaks, check the air filter box and any larger hoses carefully for cracks. You can do this easily, be patient and do a thorough job of it. Pull out a single spark plug and look at it for excessive carbon deposits. Replace with DENSO Iridium plugs that last 60K miles. Look at you spark plug wires... you will need an inexpensive multimeter to check them; Radioshack has them for cheap.

It is creating a vaccuum - clear the vaccuum by pushing air through the hose and correcting the run of hose( the way it drains)

Graham

Look for a big black box on drivers side of under hood area, maybe held by screws or clips, also loosen the screw on the metal clamp that is on the hose, after all is loosened / disassembled take out air filter and replace if needed, to check if filter is still able to function, put the light on top of filter and check from underneath, if you can see the light shining through the filter throughout the entire filter the filter is ok, if not replace it. Install is done same way but in reverse.

Whistle noise indicates a major vacuum leak. Maybe something loose in the intake system. Maybe a vacuum hose disconnected. Will explain lose of power also.

Check brake system. Resurface brake rotors. Replace pads. Check drums and shoes. Fush system. I use cross drilled rotors and carbon fiber pads. Stop in a hurry. Some Suburbans (94 and up) have slow ABS units that take their time to allow brakes to activate.

What age? What Mileage?

Brake hoses go bad and either prevent brakes from operating or prevent them from pulling back after being applied. Had this problem too.

Also check for vaccuum leaks. TBI engines had a loose metal tube under the TBI unit. I had a vaccuum leak and had to tighten my tube 6 times @ 1/4 turn each. Solved problem.

Try to use some liquid around vaccuum hoses and see if idle changes. Non TBI engines have plastic intake issues.

Check check valve in vaccuum booster. My was bad too.

Molded hose neeed to be replaced. I used two hoses and a brake booster filter in the HELP section to make the 90 degree turn from the hard line to the check valve.

93 Suburban 2WD. Runs great now. 16 mpg city.

as long as the sand was caught in the filter, and u replaced the filter..it shouldn't. it could be something as small as a collapsed or dry-rotted vaccuum hose, or as big as a bad head gasket. I would run down all of my vaccuum lines and check them first, and if they all are ok, i would take it in and have a compression test done.

This might be as simple as checking for vaccuum leaks in th e air hoses, sounds to me like when the revs drop the vaccuum stalls the car. However, could b thee resistor in the distributer. Check timing, there could be a number of reasons, low fuel pressure, plug gap, point gap, blocked fuel filter, idle stop solonoid on carby. Hope this helps, check those vaccuum lines. Good luck

Just in front of the battery there is a plastic box held in place by 2 10mm bolts. Take out those bolts and loosen the screw clamps at the throttle body and the air hose going straight down from that box. There's another box underneath that one that holds the air filter with another 10mm bolt that goes in so that it is pointed at you if you're standing in front of the van. Take that bolt out and jimmy that box out of there and you can open it up and replace the air filter.

if it isnt the iac probably the pcv valve positive crankcase vent. it is on a vacuum line somewere under hood. or check the air cleaner, the hose with the small filter underneath the air filter. i take its fuel injected?

your catalytic converter could be clogged.