TheRedEye Posted May 8 Share Posted May 8 (edited) Hi community. I recently developed a misfire after a routine battery replacement. 2004 350z GT (UK). Hadn't driven the car for a while due to bad weather, and dropped in a battery, identical new replacement for my old one. The first time I drove, after about 5 mins I slowed for some traffic lights and when nearly stopped the car tried to stall. I caught it, but then the amber engine warning light came on and I had a fairly consistent misfire. This persisted then one next drive. Following that I went to start it and had zero juice - the battery terminals were not properly connected and had slipped. Reconnected, started and the same misfire. I've read the posts about checking vacuum hoses and coil packs, which I will do. Just wondering if anyone thinks or knows whether it could be because of an electrical supply issue following the battery change? This is the only change, and the car has always been serviced and run sweet as a nut until now. Many thanks for your advice. Edited May 8 by TheRedEye correction to symptoms Quote Link to comment Share on other sites More sharing options...
mr v6 Posted May 8 Share Posted May 8 Have you scanned it for any codes? That's where I'd start. Probably a coil pack. Quote Link to comment Share on other sites More sharing options...
TheRedEye Posted May 8 Author Share Posted May 8 Hi, yes I did - should have said that's where I got the 'random / multiple misfire' - P0300. It didn't flag any particular cylinder. Rather than removing various parts off the top to get at the coilpacks, is there somewhere at the other end of each loom where they all meet and can be unplugged one at a time? I've struggled to find a diagram of for this so don't know where to look. Quote Link to comment Share on other sites More sharing options...
Cosmic73 Posted May 8 Share Posted May 8 If you've dextrose fingers and/or long nosed pliers, you may be able to unclip each coil pack clip in turn Quote Link to comment Share on other sites More sharing options...
mr v6 Posted May 9 Share Posted May 9 20 hours ago, Cosmic73 said: If you've dextrose fingers and/or long nosed pliers, you may be able to unclip each coil pack clip in turn Exactly how I do it. When you unplug one & the engine doesn't bog down, then that'll be your coil. 1 Quote Link to comment Share on other sites More sharing options...
TheRedEye Posted May 10 Author Share Posted May 10 Thanks for the advice. Looks like I've cured it (fingers crossed anyway). I replaced the PCV valve as the old one was a little overdue, worth doing anyway for a few pounds. I also fully recharged the battery, re-seated it and cleaned all the connections. I also checked all the coil pack connections were true then cleared the engine codes. Started first time and has run sweetly ever since. While I can't be certain, I think it was down to the battery disconnecting when I hit a pothole (my fault it was not properly fixed in place), which cause a total temporary loss of electrics while the engine was in cycle. That could easily throw it into a bit of a wobble. I'm back to pissing off the neighbours with my 6am starts 🙂 Quote Link to comment Share on other sites More sharing options...
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