Nissan Repair: 99 Maxima SEL will not start., cold air intake, bosch platinum

Question
My maxima has 90,000 miles on it, the OBDII reader that I bought stated it had a P300 1/2 irratic misfire, after taking it to the dealer they found nothing wrong with it and said it popped no codes on them, and that I should consider a fuel injection cleaning. So I bought a can of Seafoam cleaner and added it to my full tank of gas, my car will no longer start, I checked the OBDII once again and it stated that I had P305 1/0 misfire. All of this seem to stem from when I replaced my air system to a cold air Intake, and replace my rusty muffler with a new high flow muffler. All of my vacuum lines are attached, and I have fuel reaching the plugs, and I have spark also, I pulled my coils, and plugs 4 days ago prior to the starting failure when it was just hard to start when cold, and my plugs were all clean with no build up light carbon, but the ceramic and electrode were clean. They are bosch platinum 2's that are 3 months old the same time I added the cold air intake, Muffler. My problem was @ first the car would miss when I would floor it to get on the interstate, and If I would be at low rpm's around town (for example) 35mph in overdrive it would surge until I kicked it out of overdrive. Then within the past two weeks we had a bad snow storm hit and my car was outside, the next morning it took a spray of starting fluid to get it started. after that day it would take 8-12 seconds to start and I would have to pump it, or find the sweet spot in the gas pedal to get it to eventually start, The OBDII states P305 1/0 but now will not start, I am hoping someone has a suggestion for this so I can help the dealership itemize the problem.. Thank you, Alex.

Answer
Alex,

The multiple cylinder misfire is probably due to the plugs being defective.  I have had no luck with Bosch plugs.  Check to see if the fuel injector cleaner took out the fuel pump.  Nissan cars do not react well to fuel additives.  So, check the pressure to see if the pump is still working.  When the car runs check and change any coils that check bad.  Get a Haynes Manual to see the procedure.  Be sure to check to make sure that the MAF and air temperature sensor are hooked up properly with the new cold air intake system.