Accelerating - POP! - dash lights up, running rough, shifting bad, etc.

[AJMBLAZER]

This morning while heading to work I was accelerating onto the highway and at about 50mph I feel/hear a POP in front of me and several lights come on. Engine is misfiring and running rough.  SES light, service parking brake light, traction control off light turn on and the transmission is shifting hard. I coast off the on ramp, turn it off, and look it over. No rod sticking through the block or pan. No sign of a head gasket. Seems to be correct oil pressure when running. 

F&$@%##}#%}} I just paid it off.

117,****** miles. Oil changed every 5,000 with synthetic and mostly highway miles. 

 

Call out of work and limp it home. 

I have an ancient scan tool and it shows P0303 cylinder 3 misfire. Reset the codes. 
 

Swap the coil to cylinder 1 and put a new ACDelco plug and wire on cylinder 3. Was planning on doing plugs and wires this coming weekend ironically.

 

Runs better but not right. Lights come back on. Now the scan tool shows P0303 and P0500 which is the vehicle speed sensor. 
 

WTH?  
It wasn’t moving this time. Where’d the P0500 code come from?
 

Going to try putting a new coil on 3 and putting the cylinder 1 pack back on 1.

 

Would love some thoughts and hell, prayers.

[silveradosid]

do a compression test on cyl 3

[AJMBLAZER]

It's at a shop for that.  I eliminated all the ignition related stuff.  Waiting to hear how painful it is.