I cant figure this one out.. 02 Maxima with consistent 4-5k misfire/cutout under hard acceleration. A few weeks ago the car loss all power due to mid cat being stopped up. I replaced the 2 front cats and removed the mid cat. During this time, I also changed VC gaskets, new coils, new plugs and fresh fbjc101 injectors. After i was finished, I started the car and noticed the TB was not plugged all the way in. I plugged it in and did the relearn. However, the car runs great when cold but once its warm the misfire/stumble begins. I replaced fuel pump and nothing changed. My original injectors were fbjc100's and Im wondering if that has something to do with it. I put on a new MAF and still nothing. Drove it all day yesterday and still no SES light. Im stumped!!

 

Are you using OEM spark plugs and quality coils? Check your fuel pressure regulator and clean the engine grounds.

 

Yes, NGK plugs with Nissan coils. How do i test the regulator without just cutting the line and installing a new one? Im thinking its gotta be fuel related since its not sending a code.

 

Are you sure they aren't chinese fake injectors? Almost everything on amazon/ebay/anywhere is fake. No reason to replace injectors or coils unless they're bad.
IF you're gonna replace them, then use the green ones from 2nd gen DE and tune.

 

last time i had misfires only at higher RPMS my crank sensor came loose but it threw code.

before that I had issues with my coil connectors and had to rewire in new connectors..

 

I just put in new crank sensor a couple months ago. Ill double check it. What was bad in the coil connector

 

the connector plastic was all messed up inside and just wasn't making good contact anymore.

 

I'm having the same problem. Replaced crank and cam sensors, spark plug boots, and inspected the plugs. Still same issue with no SES light. Just P0300. I did notice that 2,4,6 had oil in the intake runners when I pulled it off to change the boots and inspect the plugs.......🤔

 

Good catch! The spark plug tube seals and valve cover gaskets are known to leak on the early VQ35's. How's your oil consumption?

 

It does smoke a little. I couldn't tell you how much oil it's using (I'm sure it is) because I bought the car and drove it home (4 miles) and have only put 11 miles on it since because of the way it runs.

 

I think its the coil connections. There's a guy on Ebay that sells a harness because he had the same issues. I will change the connectors and report back this weekend.

 

I appreciate the info! Please let me know, I just drove my car a few miles and a it warms up it runs worse and worse. I can only get it up to about 1800 rpm before it spits and sputters now.

 

Well, it wasnt the coil connectors. It runs worse now than it did before after i did the relearn steps. After it warms up, it runs like poop..no engine codes

 

Damn.....I was hoping you would've had better news. Mine definitely runs better longer in cooler weather. So i guess I'm still stuck to driving to and from work only until i can figure this out

 

I changed O2 sensors and I had a 255lph fuel pump setting around, so I slapped it in and the miss went away. I switched back to the stock pump and it started missing again. I have always thought, since I wasnt getting a SES light, that it had to be fuel related. I read on pathfinder forums guys were having the same issue and they changed the fuel damper on the fuel rails. I went to the local jy and grabbed a rear damper and will get the other one new. I will install the stock fuel pump then to see if it runs clean then.

 

Good stuff! I didn't know what the fuel damper does, but now I know.