Hey guys just got back from the shop and the code reads: P0300 - random misfiring, Okay to drive. Thats what it has on the scanner. Anyone know how I can fix this so I dont get a SES light?

 

this is What i get from Service Manual

DTC No. Trouble diagnosis name DTC detecting condition Possible causeP0300/0300 Multiple cylinder misfire detected
Improper spark plug
Insufficient compression
Incorrect fuel pressure
The injector circuit is open or shorted
Fuel injectors
Intake air leak
The ignition signal circuit is open or shorted
Lack of fuel
Signal plate
Heated oxygen sensor 1
Incorrect PCV hose connection

Cause i Had a Same Problem but only at idle RPM = NO Problem Driving ( even with NOS )
I think i had a problem with Fuel Pressure or Spark plug
cause right after i changed the 255lph SARD pump and #4 colder HKS plug
i had SES light and also my F.P is very High around 72psi at idle
F.P should be 51psi at idle

 

Most likely a vacume leak somewhere. Check your intake gaskets and fuel injector o rings. Remember, Nissan uses compression gaskets so they are NOT reuseable.

 

aaaaa....

Thank's

 

For some reason, I took my car back to the shop and have them check out my engine (I heard like a hissing sound coming from the passenger side of the engine). Well he tried to see if there was a leak so he unpluged the vac. hoses and messed around with it. He said that there was no leaks but he did hear the sound. Anyways, after we were done and I drove off, I noticed my SES light went away. Would you think it was a vac hose leak? Hopefully the SES light stays off (crossing fingers!)

 

A vac leak could cause that. Any extra air after the MAF will cause the mix in the cyl to be lean.

 

ya but my AF mixture is untuned and it is running real rich at 9.8. I am going to have it retuned to an 11.5

 

too rich can definatly cause a periodic misfire.

 

My SES light is on also. Misfire should give a blinking light, right?
Mine is continuous. Getting it looked at tomorrow. That's one of the biggest problems with FI systems....diagnosing a problem. You don't know if it is a stock issue or some problem caused by the piggy back or some hardware issue. Anyway, an occasional random misfire is no big deal. I've also just ordered the Digimoto Scan Tool. Not a bad deal for $170 including software, OBD port interface and USB-to-serialconversion cable.

www.digimoto.com

 

Misfire (non detrimental ones) do not give a blinking SES light. If you ever experience a blinking light, stop your car. A solid light means you should have it checked soon, but its not going to blow up in most cases I am also a member of the P0300 code. I drive for about 15 miles and it disappears. And for the record, I have an untuned setup for the moment (greddy).

G

 

Could you sneek a peek at the lights on the E-Manage

What do you see the lights doing?

Cheers Amy -

 

I dont have the lights on anymore. For some reason I think it was a vacume hose leak. The guy at the shop was messin with it and the lights went away after I drove off. If it does come back on, I will sneak a peak at it and I will keep you guys posted.

 

Doh! it just came back on today!

 

so how about Fuel Pressure ????
is not cost of SES light ????