Would anyone know why my tachometer register 0 RPM when I'm idling? It responds to my depressing the pedal but when I let off it goes down to 0.

 

Does the vehicle studder? or almost die? Maybe the cluster is off.. But if the Tach shows 0 and your still idling smooth then Id say its a cluster problem.. I dont fully understand your post though..

 

No stuttering or almost dying. It appears to be idling smoothly. But, I have found myself having to give it a bit more gas when backing up or beginning to accelerate so it didn't die, if that means anything.

 

Back out the air bleed screw on the throttle body a couple of turns. Also the EACV screen could be plugged.

 

^^ along with above post, reset your ECU by pulling the fuse from under the dash for a minute.

 

Do a tune up on the car.. New Air filter, plugs, wires, battery, check alt... Along with above post.. "IACV" cleaning.. maybe a vacume leak.. Its a little too general of a question for a for sure answer.. Good luck man..