Long story short: Had the dealership replace valve covers and fix some overtorqued bolts on the heads.

Dealer put everything together, started her up and the misfire problem is still there. The mechanic traced it to the clutch/flywheel area. They called me to ask permission to rip it apart; naturally I wanted to hear/see it myself.

So when I got there, this is what I heard/saw: The mechanic started the car and lifted it. While standing back, the car sounded fine. Once it was up and we walked underneath the Z, you could hear the "knocking" noise coming from the clutch/flywheel area. You could also SEE and FEEL intense shaking that was transferring to the transmission and engine area.

The mechanic believes the shaking is transferring to the crankshaft sensor causing all sorts of problems including the "multiple misfire" code to come back repeatedly.

Afterwards, we took the car out for a quick drive. As I was driving it, there was definitely misfire and loss of power under load. At idle it seemed fine at first, but after taking it on the road and getting all sorts of misfires, it continued to misfire until we brought it back and turned it off.

Anyone have any experience with this? I did a quick search and a lot of people suggested "throw-out bearing" or "normal noise for the 350." No one reported misfires or intense shaking within the other threads.

PS - I have a JWT lightweight flywheel and clutch installed; maybe 10,000 miles on it?

 

^^ @Shoji… No, it is most certainly something else more than the transmission’ throw-out-bearing.

I think your problem is with installing the new camshaft and/or the head cover.

--Spike

 

What's the story behind the over-torqued head bolts? Maybe some other work in the car's history can shed some light on this.

 

He has an other thread about the bolts.

 

Yes, there's another thread about the bolts.

I towed the vehicle to the Nissan dealership because a simple job to replace valve covers turned into 8 bolts that were over-torqued and needed to be helicoiled (spelling?). Also one of the valve covers were warped from being over-torqued and needed to be replaced then as well.

The Nissan mechanic believes he has traced the problem to the connector for the bank 1 cam shaft position sensor and two bad coil packs. He was able to put in two coil packs from another vehicle and the Z ran fine.

I don't know where I can find a cam shaft position sensor connector... been looking everywhere. Worst-case scenario I will have to purchase an entire wiring harness from Slidegood.

 

The guy at Turbo-Toys is going to hook me up with the connector. Might as well get the coil packs from him as well. Bad thing is that it will cost me $50 for the connector, but its a hell of a lot better than $200 for an entire wiring harness...