yes, it appears to be the spark plug wires. I had to change those myself a couple of
years ago, when it started to idle rough. Change the plugs at the same time to
platinum. I also changed the cap and rotor at the same time. Been running good
since. According to my 97-99 Durango/Dakota Haynes manual..(worth every penny
when it comes to electrical troubleshooting and interpreting PCM "check engine"
codes)..P300 is multiple cylinder misfire and P305 is cylinder #5.
P301 to P304 is cyl 1-4 and P305 to P308 is cyl 5-8.