[GTP Dad]

There are several possible issues here. First the coil is a definite possibility. I would change it and check and possibly replace the plugs at the same time. Second thing to check is the fuel filter. Has it been replaced. If the fuel pump is operating then the filter could be blocked and causing the engine to starve for fuel. Another possibility is a blocked Cat. If the car won't start and has fuel and spark then the cat may be blocked choking off the engine. This is probably why she had to put it into low to climb a hill. Finally, has the timing belt been changed every 70K miles. If not the car may have jumped time and the belt will need replaced and the engine put into correct timing. Just a few places to look at when trying to repair this one.