Motor mounts would be mostly from low speed to high, as you accelerate, and there is the most reverse torque on the enging. At steady high speed you won't notice bad motor mounts much.
Fuel filter or pump comes to mind first, because you need the most fuel under load.
There are also a number of valves that could be causing loss of intake vacuum as well, such as EGR, purge valve, PCV valve.
Make sure spark is good and plugs good. A smaller gap will perform better, and only hurt mileage.
You can try cleaning the MAS sensor, and take a look at the oxygen sensor. These can be checked with an ohmmeter, but I don't have the actual values. But if you get 0 or infinite resistence, there is probably a problem.
Rough running often means it is isolated to one cylinder. Try removing one plugwire at a time to see if one makes no difference. Then try switching plugs to see if problem moves with plug.
Answers & Comments
Motor mounts would be mostly from low speed to high, as you accelerate, and there is the most reverse torque on the enging. At steady high speed you won't notice bad motor mounts much.
Fuel filter or pump comes to mind first, because you need the most fuel under load.
There are also a number of valves that could be causing loss of intake vacuum as well, such as EGR, purge valve, PCV valve.
Make sure spark is good and plugs good. A smaller gap will perform better, and only hurt mileage.
You can try cleaning the MAS sensor, and take a look at the oxygen sensor. These can be checked with an ohmmeter, but I don't have the actual values. But if you get 0 or infinite resistence, there is probably a problem.
Rough running often means it is isolated to one cylinder. Try removing one plugwire at a time to see if one makes no difference. Then try switching plugs to see if problem moves with plug.