P1320 and a P0300 code on 01 pathfinder se 3.5l

[dflipmode]

The symptoms that i have are the same as a misfire condition. You can feel it at idle, vehicle shakes at around 50mph at steady speed, shakes as well above the 60mph range. I have the code p1320 and a p0300. It doesnt tell me which specific cylinder. I have tried taking the harness off each cylinder while the vehicle is idling to see if there is any changes to the rpm and possibly figure out which cylinder would stay the same at idle even when disconnected, but no luck. I have changed the air filter before to a K&N and it might be possible that the MAF sensor is dirty. But other than that, I have followed every step according to the service manual as to what to check for and still no luck. The only thing that I have found before when I changed the plugs is that #3 plug is white compared to the others, so that is a possibility that it might be a fuel problem? But other than that, I dont have a clue. I refuse to follow what the damn dealer says and just replace all the coils because it is a waste of my money if that is not the problem and if anybody else have any input, that would be great. thanksdennis

[dflipmode]

I have the checked the resistance values of all the coils when I changed all the plugs and they are all similar in resistance values. I have checked them in cold condition( after the car has been sitting overnight) and hot condition(just after being driven) and the are all the same. I have checked the fuel filter as well and its not clogged up. I dont know what else to check for. I have followed the service manual step by step from the harness to the relay to the coils and the plugs, but found nothing out of whack. Any other thoughts? I dont want to replace the coils yet if they are not the problem. Dennis

[jetroy240]

That's always the recommended fix when u get a code P1320 & P0300, replace all coils. Unless u can pin point the coil w/ is malfunctioning. Well, u can buy one coil & install it one at a time on all cylinders to isolate the bad one. It's possible it's not the coil, could be the connector or circuit or ecu too.

[SteveTheTech]

Hey there, A P1320 is an intermittent break in communication. You can try to diagnose this down to one coil. However the best way to fix this once and for all is to replace all the coils, since they are all at the same degradation rate. Inevitably if you replace one they will all start to fail, they just do that.

Good Luck