Hi Scotty, I just found your channel recently and am enjoying your videos immensely! Your logic makes sense, your diagnostic's are sound, and you really do seem impartial - great job!!!👍

I have a 2004 Nissan Frontier crew cab 4x4 p/u with the normally aspirated V6 (VG33E) engine. (I know, I shoulda bought a Toyota, but I couldn't find on at a decent price, lol.)

I'm in NY and bought it in Jan 2014 with 65k on it from the original owner. The ck engine lite was on with a P0455 gross evap leak - which I can usually smell gas along the bed near the filler. The lite occasionally goes out for a day or so, so I assume it's the vent valve sticking open. I've been getting it inspected by resetting the codes and driving just the right amount of miles to have enough systems up to pass.😉

Along with that code I have also always had the knock sensor code, which I'm told on these engines is always present and won't set off the ck eng lite.

In June 2016 @ 105k my friends and I did the timing belt, water pump, thermostat, plugs, wires, dist cap & rotor, fuel filter, rear shocks, fan belts and anti-freeze.

The truck has developed a random misfire, code P0300 - which when it's missing flashes the ck eng lite, rendering it UNDRIVABLE! This usually only happens when its cold out, less than ~40°F. It happens both when the eng is cold, or more often after being driven more than long enough to be up at normal operating temp.

Now for the really weird part: when it happens if I just shut it down and sit for 10 minutes and restart, it will usually run fine the rest of the day!!! WTF???

I have been dealing with this for 2 winters now - even dealer mechanics have no clue when I describe the symptoms... They just cite the usual suspects: plugs, wires, the distributor... (Which btw, seems to have NO play in the shaft.) And of course I don't want to take it somewhere and just start throwing money into it as randomly as it's misfiring, lol.

I'm up to 160k on it, and besides this problem (and a rusted rear bumper) the truck is clean and sound, and I like it.

I am considering changing the coil and the power transistor/modual/cam sensor, but I'm COMPLETELY baffled and would appreciate any possible causes you can think of!!! Thanks in advance! Charlie

P.S. Is there any chance the vent valve can effect gas mileage - or even be the underlying cause of this misfire, either by messing with the intake manifold vacuum thru the purge valve in the engine compartment, or can this somehow effect fuel pump pressure???