Engine problem in neutral

Just got my car back from the shop. They removed the cross threaded spark plugs and replaced them with new ones. After that the same day my distributor went bad but I went and got a replacement. Now today I started up the car and idle was at 1800 rpm. The car has a hard start. I do get sparks, fuel is coming, the starter is working and no leaks. Only problem is high rpm when starting but goes down to 600-800 rpm when idle. Cannot step on the gas when the car is in neutral, if I do the engine makes a funny sound and dies along with a backfire. Car can only be gased when in gear and be driven. The engine has a rough idle and shakes. All of the engine mounts are fine, fuses are ok, but I can’t get the problem solve. Vehicle is a 93 GS. Replacement distributor is from a 94. Vehicle is stock with no mods. Distributor been advanced and retard to test. I can smell gas from the car so I am running rich.
Has anyone encounter this problem or know how to fix it.

Thanks if anyone can figure out what going on.