Cannot read OBD 2 Port

[Bwwaaaa]

Ok bare with me, this will be a fairly long explanation but this is becoming an incredibly complicated issue that I cannot resolve.

This issue is on my 1998 318ti, M44 engine.

I was driving home from Bimmerfest when I was cutoff and had to slam on my brakes. After slamming on my brakes my car through up a Check Engine Light and started misfiring horribly on acceleration.

I pulled over, turned off the car and then turned it back on. It started giving me an "Oil Service" notification which is something I have never seen this car give me (andI had just done an oil change before the trip).

The car was bucking very badly on acceleration and it was difficult to drive. I made it home, but it was still a pain. The next day I go to read the CEL with the OBD2 port and the Craftsman reader says it cannot establish a link. I take it to Autozone, their reader says the same thing. Mind you, I've read a CEL on Autozone readers in the past.

None of the fuses seem to be out, which was my first thought. All the grounds look fine. Today I took it to a shop out of frustration, and even they said there should be no reason it isn't reading.

I'm at a complete loss. The car is barely driving, I can't read the CEL and I'm not sure where to go from here. The latest symptom is the gas gauge, the temp gauge and the brake lights all stopped working.

I don't know how any of this is connected, but this is becoming a real head ache. If anyone has any suggestion on where to start with this, please let me know.