Misfiring problems...injector circut open

Backround info: I have a 96 XJ SE 2WD with 205k miles on it. About 3-4k ago I did a 2000 intake swap, but I used older style injectors. My engine has been running hot lately about 220-230 if I don't put the heat on, and I have hood vents installed.

Problem: My XJ began to run rough and my CEL came on I checked it out with a OBDII scanner and pulled codes "P0205 injector circut open cylinder 5", "P0300 random\multiple cylinder misfire", and "P0305 cylinder 5 misfire". This was 5 days ago. This morning I got 10 codes. Every cylinder had misfired at one point, and cylinders 1,2,5,6 had injector open circut codes. I've checked my wire harness and don't see any visible damage. The injectors are only 4k old and have run flalessly all that time. Any suggestions would be extremly helpful.:helpme:

One thing to chech is the condition of the pins in the wiring connectors on the injectors. If the pins are dirty or loose then vibration from driving may cause an intermittent open in the harness causing the computer to store the codes you are experiencing!

I just checked them and they're all good.

The next thing to check is the connetors at the computer if you have not done so already.