06 Rev-Up Sputtering Under WOT. Code is "Multiple Cylinder Misfire" What's the cause?
 

So a buddy of mine recently bought an 06 350Z Rev-Up with only 32K on the clock. He was having some issues starting it (took like 2-3 times more cranks than my car, even when warm). We ended up finding the battery was a AAA replacement battery that looked much smaller than OEM. He put a brand new battery in but it didn't seem to help the issue.

We then did a spirited run up in the mountains on Christmas day. We stopped at the top and let the cars cool down a bit. When we went to head back down, he got about 100 feet and pulled off the road. Found out his car threw an SES light and was sputtering quite a bit. We let it sit for a few minutes and it started up and ran ok, but on the way home he said it would start sputtering anytime he got on it. He got the code pulled and it was a general "multiple cylinder misfire." Nothing else.

Any advice on what it could be? I'm going to pull his spark plugs to make sure they are all in good shape and also check out the coils while I'm down there, but I figured I'd get some advice from you guys first.

Thanks

Revo

My first guess would be check the obvious first. Sparks, coils/wire, & injector.

How would I go about checking injectors?

Usually with the motor running get a screw driver or something similar & place it on the injector & listen with the other end. Should be a clicking sound.

I would check spark first by pulling one plug at a time and resting them on the chassis and turning the car over. I had this on my Z once and it ended up being all three cylinders in one side had no spark. Car drove fine other than under load and had the same SES.