Im getting OBD2 code for Misfire- (multiple cylinders) Check engine light is on.
*complete tune up with Plugs, wires, rotor, cap and oil change done
*K&N cold intake installed
*Premium gas being used.

the truck starts, runs excellent.Has lots of power, no hesitation or lag. I erased the OBD2 codes and the check engine light came right back on within 4-5 warm up cycles. Why? can anyone help me?

you probably need a new distributor,how many miles do you have?

155650miles. Just got a new timing belt installed, New waterpump.

pull the cap -rotor and black ring with the electronic out and look in the very bottom of the dist any black dust or loose parts?

Im getting OBD2 code for Misfire- (multiple cylinders) Check engine light is on.
*complete tune up with Plugs, wires, rotor, cap and oil change done
*K&N cold intake installed
*Premium gas being used.

the truck starts, runs excellent.Has lots of power, no hesitation or lag. I erased the OBD2 codes and the check engine light came right back on within 4-5 warm up cycles. Why? can anyone help me?

Oil from the K&N Filter may have fouled the MAF sensor.

I don't see if you have the SC or not...if not, the use of premium fuel can lead to fouling in the engine from unburned hydrocarbons.

Checking in the rotor, as recommended, is a good start, but I'm throwing the other stuff out there in case that doesn't pan out.

I took the Mass Airflow Sensor off and cleaned it, Checked for vacuum leaks with Starting fluid, Its not SC so I will run a couple of tanks of Premium gas and re-check the OBD code to see if it is still misfiring.

Well if your engine is running great then you dont have a misfire. If you did have a misfire your CEL would be blinking because there would be gas making it to your cats. Doesnt the knock sensor sometimes cause a misfire code?

I dont think premium gas is helping. The na engine's compression is tuned for regular. Premium gas wont burn as good... unless the computer adjusts for the premium and advances the timing. I know toyotas can do that but IDK if nissans do. But not to be all negative the premium can help clean the engine out :-)

-Clint

So I cleaned the Mass air flow sensor, took the cap and rotor off and inspected for loose parts or any abnormalities in the distributor, (none that i can see visually) checked for vacuum leaks by spraying starter fluid around the hoses, cleaned the throttle body control.. still getting the misfire p300 code and the knock sensor (highbank) code. WTF?