I just replaced 2 motor mounts, the tensioner,and 2 02 sensors but car vibrates really bad while driving and at stop in drive what could be causing the vibration?

motor mount need to change asap before it damage more parts.

Bad O2 sensors affect the fuel/air mixture. Vibrations can be caused by many sources, hard to diagnose here. To test the motor mounts. apply the parking brake, open the hood. Put the car in drive and step on the brake with one foot while applying full throttle with the gas pedal. Watch for excessive engine lifting on one side. Be careful not to have the engine fan to contact the shroud. Now do the same in reverse. If the engine lifts excessively, your mounts are shot. If the engine stays put with only a slight movement from torque, then the mounts are good.

Sounds like maybe a busted motor mount or transmission mount, or a worn out cv drive axle.Look under the front of the car at the drive axles there is 4 rubber boots 2 on each axle inner boot and outer boot.See if one or more of the boots is torn or split.

The rattle is caused because the rpm is lower. When stopped in drive with one foot on the brake, press the throttle down slowly until the vibration stops and the noise goes away. Cause? Weak or bad motor mounts, loose bolts or parts.

Vibration at idle brings to mind a few suspects:

transmission mount(s) broken/missing
transmission internally worn
motor mount(s) broken/missing

(1) transmission internally worn or transmission mount broken/missing - test this by shifting into neutral at the next stop light. If the vibration disappears when you disengage the transmission, then the transmission is the source of the vibration. You'll have to inspect the transmission mounts - if they're ok, then the transmission is internally worn and can no longer smoothly "slip" while idling in drive.
(2) motor mount broken/missing - also test this by shifting into neutral at the next stop light. If the vibration persists, then the transmission is exonerated, and the vibration is coming from (under) the engine. The rubber part of motor mounts commonly crack/break and or pop out and are lost.

A photo of the front motor mount for the 2003 Dodge Neon:

The belt tensioner can cause many of these problems, sometimes the serpentine or fan belt is replaced, but the tensioner is not given much thought, a tensioner that is going out, can cause the belt to not have enough tension to keep the battery charged by slipping, when the clutch on the ac compressor cycles on and off, if the tensioner is to loose, or not tight enough can cause the compressor to vibrate, it can cause wear on other parts attached to the belt even cause pre-mature wear on other pulleys. good luck!

The O2 sensor answers the idle problem. The vibration could be motor mounts, bushings in the sway bar or even tie rod ends or a bad strut. If the vibration is only there when moving it's not the motor mounts but the rest are still suspect.

This engine does not have a harmonic balancer. This is the cause of the rough in gear idle with the automatic transmission.

Does the car stall on hard stops or turns? when it is in park does it shake less than when it is in gear.. If it shakes more while driving, it may be the tensioner, which is the bracket that is with the belt next to the alternator. sometime when driving it may squeak, then stop completly. If it just shakes, then it is your motor mounts. try tightning them and see if they are corroded. you may need to replace them

Broken or worn out engine mounts will cause allot of engine vibration in drive at idle, reverse also, change all 4 the mounts, not just the 2 broken ones. As far as slow acceleration no mounts will not cause that, Have you reached the 100,000 mile recommended tune up? have you ever replaced the fuel filter, this is required every 30,000, let me know.