Idle low idle goes low. sometimes stalls

This can be either an engine management issue (bad idle air control) or a transmission issue if an automatic trans (torque converter lock up problem). Idle air control can often be cleaned so = cheap fix. Trans problem not so easy.

This sounds like the idle control valve or stepper motor as it's sometimes called needing a good clean out or replacement. When faulty this would cause all the symptoms you are describing.

How long since a tune-up? Any applicable trouble codes? With extended crank, you can try cycling the key, on and off, a few times before you crank it. If that helps, have to check fuel system. Use a gage and check proper fuel pressure.
Check and clean the idle air system, see if it helps?

I would check either the idle air control valve or the throttle postion sensor. Is the check engine light on?

Do you have a check engine light? Which engine? My 1996 Trooper with a 3.2 D.O.H.C. is awful for plugging up the E.G.R. I have cleaned it several times! Good Luck!

near the throttle body there is an adjusting screw(flat head) for air fuel mixture, it's on a deep cavity sometimes with a cover, adjust counterclockwise will increase the idle.

Here are some of the causes of surges, stalls at stops, slow idle speed, erratic idle speed, rough idle and engine hesitation (and other problems), it is in most cases the idle speed control air-bypass valve and or throttle valve and upper intake, these area's get full of gunk and combustion residue over the miles and cause idle issues (stalls, low idle) like yours, Get a can of intake cleaner from any local parts store, not carb spray, intake cleaner, it is made by a company called CRC, remove the air intake hose to the engine, hold the idle high so the engine won't stall, then spray the can of cleaner into the intake while keeping the engine running, use at least 1/2 the can, shut down the engine and disconnect the battery for 5 minutes, then restart and complete a number of mixed driving cycles, town, freeway, stop and go etc., after a few days the problem will go away as the system will relearn to the clean intake

TRY THIS AND LET ME KNOW IF IT CORRECTS YOUR PROBLEM
Here is the most common cause of surges and stalls at stops and low erratic idle speed and rough idle, it is the idle speed control air-bypass valve and throttle valve (IAC for short), they get full of gunk over the miles and cause idle issues (stalls, low idle) like yours, Get a can of intake cleaner from any local parts store, not carb spray, intake cleaner, it is made by a company called CRC, remove the air intake hose to the engine, hold the idle high so the engine won't stall, then spray the can of cleaner into the intake while keeping the engine running, use at least 1/2 the can, shut down the engine and disconnect the battery for 5 minutes, then restart and complete a number of mixed driving cycles, town, freeway, stop and go etc., after a few days the problem will go away as the system will relearn to the clean intake

THis has happened to me in the past. My fix was to clean the throttle body. The problem began after my battery died. The computer was defaulted back to its original settings after replacing the battery. Once I cleaned the throttle body, everything was fine. This happened at about 85,000 miles.

sounds like the idle air control motor.typical symtoms for this motor is rough idle when cold.