Please describe how to put a sperpentine belt on a 2003 Hyundai Santa Fe 3.5

This is a common issue and the fix is on this site already. When this link:

Questions Answers for Hyundai Santa Fe timing marks diagram

"POP" LIKE A BACKFIRE???.....TIMING BELT IS 1 OR MORE TEETH OFF

Yes it has an interference motor

There are several possible causes for the drivability issue you describe. I'd be guessing at this point with the limited information here. Best advice, take it to an authorized Hyundai Service Department & have it properly diagnosed. This way you'll find out exactly what the problem is and what it will take to fix it.

Timing belt or serpetine belt...Either way, I'd buy a Chilton's Manual at Auto Zone or NAPA ($25) it should describe everything in detail.
Good Luck

First of all, the particular vehicle you describe (2003 Santa Fe) came with three different engines (the 2.4 (4 cyl), the 2.7 (6 Cyl) and the 3.5 (6 cyl). Which one is it? NOW!.. Which belt are you talking about?

its your serpentine belt (thats what its called) and you will need a 3/8 ratchet and then find the belt tensioner. The tensioner has a spot where you need to put the ratchet into and pull or push depending on whatever way and that will releive the pressure off the belt so you can take it off.

hi the sensor is in with the timing belt. You will have to remove the timing belt cover and belt to put a new one in. You will also see a small gold metal rotor that spins on this sensor also replace that or it will trash the new sensor.

Sounds like the timming belt jumped or broke. A faulty crank sensor could also be at fault.

When asking a question about a problem with your vehicle you should always state your vehicles od reading and engine size, thanks.

You can drive it till it breaks of course, that will cost much more then replacing it as maintenance though. I would plan to have it changed much sooner then later as you are already past your recomended service time.