Jumped timing repaired was running great now it is running badly

Why did your car jump timing? Did you re-time the belt yourself and replace the belt tensioner? If there was a problem with the timing belt tensioner and you did not replace it along with a new belt, it will just happen again. Anymore details on the previous repair?

This is also an interference engine, meaning if the timing belt breaks or jumps it will cause the piston to come into contact with the valves and bend them.

First have the PCM scanned to see if there is any diagnostic trouble codes stored. Even if the check engine light isn't on right now. Also did you get a new timing belt or did you use the old one with the old tensioner? The reason I ask is if the front main seal is leaking oil and the belt got oil soaked it will stretch, which is why I was wondering why it jumped timing to begin with?

That being said, the Tachometer gets its signal from the Crankshaft position sensor, which also controls Fuel injector timing and ignition control, so if the crankshaft sensor is on its way out it can cause the engine to run rough. The camshaft position sensor can also cause the engine to run rough but doesn't control the tachometer signal to ECM.

Well you really should have the computer scanned for codes, if it is running that bad, there should be a code set in there that will lead you in one direction or another. Checking sensors for glitches and drop outs can be tough without the proper diagnostic equipment. I dont want to lead you in the wrong direction. You haven't said if the check engine light is on or not yet. If you go to Autozone or a parts store, most of them will scan the PCM for free, if there is a code for the crank sensor or something else, it will give you an idea of whats going on. Again I don't want to lead you in the wrong direction. Checking a cranksensor, I would use a lap scope to watch its wave for glitches or drop outs, if there is a code for it in the computer it would be safe to say it has gone bad. Here is an example of what we would be looking for with a lab scope on a sensor (picture 1). MORE INFORMATION is needed to be able to help you. But if you want to check the crankshaft sensor, it is located on the bell housing of the transmission on the back of the engine (picture 2). With the sensor plugged in, back probe the sensor wire and watch for a pulse with a test light while cranking the engine over. Another test is to unplug the sensor and check the resistance of the sensor to make sure it isn't an open circuit inside the sensor itself. Here is another wiring diagram of both the crank and cam sensor. The wires to check are highlighted in yellow(picture 3). Check for a pulse from both sensors.