Because 1998 Saturns suck. I have one, so I should know ;) Honestly, it's either your throttle, a clogged fuel line or a misfiring spark plug. It is common for the upper motor mount to wear out and cause excessive vibration especially at low RPMs. It is easy to replace yourself at a cost of about $90. It is in plain view and located on the belt and accessories side of the engine. To replace, first support the engine from underneath with a jack and block of wood on the oil pan. Second, remove the bolts on the motor mount and install new mount and the bolts supplied. Third, make sure you torque the bolts to the proper specs. That's it! It took me about 45 minutes. Immediate improvement in noise and vibration.
How many 3s in 313433535333?
Is it true that one human year is equal to seven dog years?
If you are 13 years old when were you born?
Who would you swap lives with for a day?