'04 santa fe V6 2.7 AWD. Runs fine 5 days straight. Sits from Fri-Sun unused. On Sunday when I go to fill up for the week of driving, I have a hard time starting. Once started, Rpms wont go any higher than 3000rpm and no faster than 20-25 mph without sputtering out. I pull over, shut it off. Pump gas pedal 3-4 times, car starts right up and no more problems. What is this? Not only that, when I bring it to the mechanic,he looks at me like I have 2 heads? Please help

I suggest hooking it to a scan tool that will access the ABS/ BCM functions of the PC and find out what code it is showing. That will lead you to what the issue is.

We are in California but here is what is listed.
645 Grapevine Highway Hurst, TX 76054 Directions Closed · Opens 8 AM FriHours this week Today 8 AM-5 PM Fri 8 AM-5 PM Sat 7 AM-7 PM Sun 11 AM-4 PM Hours week of Oct 31 Mon 7 AM-7 PM Tue 7 AM-7 PM Wed 7 AM-7 PM Thu 7 AM-7 PM Fri 7 AM-7 PM Last day to vote early at this location is Nov 4 B 828 West Harwood Road Hurst, TX 76054 Directions Closed · Opens 7 AM MonHours week of Oct 31 Mon 7 AM-7 PM Tue 7 AM-7 PM Wed 7 AM-7 PM Thu 7 AM-7 PM Last day to vote early at this location is Nov 3 C 5350 Basswood Boulevard Fort Worth, TX 76137 Directions Closed · Opens 8 AM FriHours this week Today 8 AM-5 PM Fri 8 AM-5 PM Sat 7 AM-7 PM Sun 11 AM-4 PM Hours week of Oct 31 Mon 7 AM-7 PM Tue 7 AM-7 PM Wed 7 AM-7 PM Thu 7 AM-7 PM Fri 7 AM-7 PM Last day to vote early at this location is Nov 4 100 Main Street Colleyville, TX 76034 Directions Closed · Opens 8 AM FriHours this week Today 8 AM-5 PM Fri 8 AM-5 PM Sat 7 AM-7 PM Sun 11 AM-4 PM Hours week of Oct 31 Mon 7 AM-7 PM Tue 7 AM-7 PM Wed 7 AM-7 PM Thu 7 AM-7 PM Fri 7 AM-7 PM Last day to vote early at this location is Nov 4 6801 Glenview Drive North Richland Hills, TX 76180 Directions Closed · Opens 8 AM FriHours this week Today 8 AM-5 PM Fri 8 AM-5 PM Sat 7 AM-7 PM Sun 11 AM-4 PM Hours week of Oct 31 Mon 7 AM-7 PM Tue 7 AM-7 PM Wed 7 AM-7 PM Thu 7 AM-7 PM Fri 7 AM-7 PM Last day to vote early at this location is Nov 4 1100 Bear Creek Parkway Keller, TX 76248 Directions Closed · Opens 8 AM FriHours this week Today 8 AM-5 PM Fri 8 AM-5 PM Sat 7 AM-7 PM Sun 11 AM-4 PM Hours week of Oct 31 Mon 7 AM-7 PM Tue 7 AM-7 PM Wed 7 AM-7 PM Thu 7 AM-7 PM Fri 7 AM-7 PM Last day to vote early at this location is Nov 4 700 Mary Drive Hurst, TX 76053 Directions Closed · Opens 8 AM FriHours this week Today 8 AM-5 PM Fri 8 AM-5 PM Sat 7 AM-7 PM Sun 11 AM-4 PM Hours week of Oct 31 Mon 7 AM-7 PM Tue 7 AM-7 PM Wed 7 AM-7 PM Thu 7 AM-7 PM Fri 7 AM-7 PM Last day to vote early at this location is Nov 4 2424 Forest Ridge Drive Bedford, TX 76021 Directions Closed · Opens 8 AM FriHours this week Today 8 AM-5 PM Fri 8 AM-5 PM Sat 7 AM-7 PM Sun 11 AM-4 PM Hours week of Oct 31 Mon 7 AM-7 PM Tue 7 AM-7 PM Wed 7 AM-7 PM Thu 7 AM-7 PM Fri 7 AM-7 PM Last day to vote early at this location is Nov 4 3201 Friendly Lane Haltom City, TX 76117 Directions Closed · Opens 8 AM FriHours this week Today 8 AM-5 PM Fri 8 AM-5 PM Sat 7 AM-7 PM Sun 11 AM-4 PM Hours week of Oct 31 Mon 7 AM-7 PM Tue 7 AM-7 PM Wed 7 AM-7 PM Thu 7 AM-7 PM Fri 7 AM-7 PM Last day to vote early at this location is Nov 4 201 North Ector Drive Euless, TX 76039 Directions Closed · Opens 8 AM Fri

Checked how? Some AWD drive cases are fed fluid from the transmission. Some are separate. I haven't seen any rebuilt yet. these cases aren't much. The controls are in the rear differential and transmission.

could be bad oil flow. maybe a clogged oil pump and or pick up line

The Check Engine Light does not have to come on for someone to find out what is wrong. A shop may have to have the car for a few days so they can run some tests on your fuel and ignition systems. They will most likely have to drive the car/run the engine to duplicate the symptom so they can catch it while it is malfunctioning. Intermittent problems can be very elusive, but they can be diagnosed with a little patience. The level of your fuel gauge most likely has nothing to do with your starting problem.

it was running then you removed the gas cap to fill ( extremely dangerous practice with car running)
that indicates that there is a problem with the EVAP system.
run the fault codes ( what the dealers should have done first ) and check for the EVAP codes , purge vent or solenoid problems

The most common cause of this is thermal shock (gasoline is very cold out of the ground) to the electric fuel pump inside the fuel tank, when the pumps get worn the decrease in temperature from the gasoline causes the pump to stick. This is a question I see fairly often, so I did research to see what the common cause is. Next time this happens have the fuel pressure checked.

seems like engine goes to "save run" mode. the reason why is stored in the onboad computer usualy. have someone read that error code with an OBD interface, and act accoringly to that code.

There no four wheel drive button, it's permanent AWD

sounds like a fusible link in a harness under the hood. hard to find , i wuold take to an auto/elec specialist Good luck...