2003 Nissan Maxima • 130,000 miles

At random my car will misfire and through a p300. I have sent all the injectors in to be checked. They checkout great. I replaced all the coils. All cats were replaced. I replaced the crank sensor. I also replaced the fuel pump and filter. I also put an 2004 rear valve cover on to fix th 2003 oil leak. When the car is running fine the output voltage is 14.1-14.0. When it is running rough it drops down to 13.7-13.6. The mass air flow sensor is also new. Running out of options.
June 17, 2013.

As this can be many things that cause this have a pro scan it so he can narrow things down.

Jun 18, 2013.
I have scanned and reviewed all live data. Everything is within spec both when it is running rough or smooth.

Jun 23, 2013.
If you don't have a pro type scanner it won't pick up what needs to be. Your maf can be bad as well as low compression on cylinder, a lean injector etc. If you have an auto parts type scanner it can't read a lot of that stuff. Fuel pressure must be within spec as well and check all grommets for air leaks.

Jun 24, 2013.