Hyundai Sonate engine vibration

I have a 1997 Hyundai Sonata. The whole car and the engine vibrates
whenever I stop or/and on drive only. It uses about a gallon per 5 miles.
I checked every part of the engine and I know that it is not leaking any
gas. I suspect the throttle position sensor could cause some vibration
but what of the gas per mile problem?

 

I would get the ignition leads checked.

 

Do you have a check engine lamp on? Have you scanned for codes?

 

The engine check lamp is on. The code inititially pointed to the throttle
position sensor, however, the problem was not corrected even after I
replaced the sensor.

 

I believe the sensor on this car is adjustable. Did you notice whether
it's adjustable, and if so, are you sure it's adjusted properly? I
presume you cleared the codes and none returned.