2000 Hyundai Accent - OBDII port not working - Engine light on - Help Please?
 

So I just got a (mostly) running 2000 Hyundai Accent 5 speed on Saturday the 4th, had it on the road since Monday the 6th. Car ran like a dog, I mean utterly terrible, but I traded my 1974 GMC for it because the driveshaft almost fell out of that truck when the center bearing went, and after a laundry list of parts I'd thrown at that truck, I was done. I'll do a "Hey, I exist as a Hyundai owner now" thread later. Side note, I hated this car when I first got it because it ran like a dog, since I've replaced the spark plug wires, I've been having a blast.

So anyway, long story short, I was getting a whole mess of codes with the car, until I replaced the spark plug wires, then I got a code for Misfire on Cylinder 1.. And now suddenly my OBDII port won't work with any scanner. Tried my Bluetooth scanner, took it to O'reily's and autozone. Checked a ton of fuses but I can't seem to find a single dead fuse. Any help on how to diagnose this would be nice 'cause the car still has a wicked stumble at times and I'm just relearning to drive a stick after almost 10 years so sometimes when the car bucks I stall it. Also I'm only getting about 19 miles to the gallon but that's probably the way I drive more than anything. I know the MAF or an 02 sensor could cause this, but I can't plug it in to see what's wrong sooooo, I'm hitting my head on a wall right now. Can I diagnose the 02 or MAF with just a multimeter? I haven't had time to look into this because I missed 3 days of work where my truck tried to rid its self of it's own drive shaft, and I've been running the balls off this poor little Hyundai.

The following has been replaced:

Spark Plugs
Spark Plug Wires
Fuel Filter (According to previous owner)
Air filter (Previous owner)

Things I know need to be replaced:

Exhaust manifold gasket

Look at data link connector with multi-meter
Pin 16 is constant 12 volts
Pin 4 is chassis ground
Following there are three pairs of signals
pin 15 and 7
pin 14 and 6
pin 10 and 2

Look at the connector to see if pins are bent
They might not be making good contact

Mis-fire on cylinder 1 would not be the MAF or the O2 sensors as these should affect all cylinders
I would take a wild guess and say vacuum leak on cylinder 1 in-take manifold gasket
Or spark plug wire is shorting. swap plug wires or spray water on wire to see if it gets worse.
Good luck

I got both issued sorted, the fuse that provides power to the OBD2 port was heavily corroded, also misfire on cylinder one was due to a bad spark plug, which was funny 'cause they where supposedly replaced by the previous owner. Car is running great now, no issues.

Thanks for the update