Yukon was running and all the sudden died started up service engine light came on idles super low in gear and dies unless you put foot on gas and brake if stopped

IAC - idle air control problem possibly .( You can drive it if you use your left foot to brake but keep the gas pedal down to keep the RPMs up.) Wouldn't be a fuel filter , if fuel filter was clogged partly it would idle ,but would lack power ,low fuel pressure at higher speed's . Do you know what IAC valve is ,an how it works ?
Idle Air Control Valve
Or maybe the EGR valve pintle is covered with carbon an sticking open .
Or possibly a dirty or bad MAF sensor - mass air flow sensor - the PCM - engine computer needs info from this sensor so it know's how much fuel to feed the engine .
Hooking up a professional type scan tool to view engine sensor data cut's down on guessing as too what the problem is .

007 Idle Speed Problems Scan Data for Idle

There are a few possibility on this one. If you run it out of gas or really low on gas you could of sucked junk up from the bottom of the tank and you will need to replace your fuel filter. Another is that your fuel pump us going bad and you would need to check the pressure. Your throttle position sensor may have gone bad. Your idle control valve is another. Your map sensor or mas sensor could be bad

To start with, you have a throttle body instead of a carburetor.
On that throttle body is a component called an air control valve.
That valve is how the computer controls the idle speed. It should open and close the air flow into the intake manifold as needed.
Is the check engine light on when you are driving ? Have you checked the fuel pressure ?

Hi, this problem can be caused by a broken fuel pressure regulator diaphragm. With the engine running, remove the vacuum line from the regulator. If gas comes out of the regulator at the vacuum port, replace the regulator.

You need to get the trouble codes out of the computer first. Take it to your local autoparts store and they can hook up a scan tool and retreive codes this give you a general area start looking for the problem.

Possible areas of concern are:

• faulty MAF (Mass Air Flo) sensor
• bad EGR (Exhaust Gas Recirculator
• bad TPS

It's most likely a combination of the 3 but the main cause would normally be the TPS (Throttle Positioning Sensor) which regulates engine idle speeds under different conditions.

Sounds like a vacuum problem with the transmission. Modulator maybe?
Take it to an auto trans specialist.

you could try to clean the mass air flow sensor

A faulty gas cap can cause the sensor to come on.
Clean out the throttle body with a cleaner and see if the idle improves.

if the battery voltage gets low the computer will lose its memory...the idle air control is not ure what to do.. drive the vehicle for a while ...you may have to 2 foot it but eventually it should idle