Hi Andreau welcome to the forum!,
First of all I would advise you to use the E-brake at all times instead of putting the weight of the car on the transmission; this is not a good idea as it might cause long term damage.
If the shifting lever wobbles all the time and is hard to move, it is very likely that the Torx bolts holding the lever to the linkage are loose and need to be retightened. You need to take a look under the dashboard (remove the kick panel) while moving the lever or ask someone to do it. You will see where the problem is very easily. As stated before I think the Torx bit size is T10 or T15. Just thighten the 2 bolts and you should be good to go.
About the other problem I'm pretty sure the EGR channels are clogged. It is a common problem with 91-95 4.6L engines.
Take a look at
THIS LINK
Also pay attention to a rubber tee connection the PCV valve (on top of the passenger side valve cover) to the back of the throttle body. This is another common problem on 91 to 94 and some early 95 models.
Oscar.