So ive been fighting an intermittent misfire for ever...

Ommateal · 03-12-2020, 01:06 AM

Quote:

Originally Posted by 10MPlayer

Over a month since the dealer replaced the bad fuel pump and the car is working fine. There haven't been any 100F degree days but so far no problems with sputtering and misfiring on restart. In fact, the car seems to have gained 20 or more horsepower. Low speed response is much better. The best part is I found out that the extended warrantee I bought was still in effect and I ended up paying $0.00 for the whole thing. The dealer got it right. Hope this helps.

That is amazing to hear man! Im getting ready to pull mine out for the summer and hopefully get it fixed as I still have the issue as far as I know... at this point ive done so many little things ive lost track... I have some extra cash to spend that I have been saving so this might help, but I hope I dont have to keep dumping money into it, I really wish I had a very knowledgeable Z person local to help me fix this haha, I don't trust the dealer here, they werent ever able to give me a solid answer.

Corsairprime · 12-10-2020, 08:03 AM

My P0171 and P0174 problem was caused by fake Denso Iridium FXE24HR11 spark plugs. The electrodes on all of these fake plugs had melted to a gap of .075 to .080. I did buy new genuine plugs from NGK, the Laser Iridium DF8H-11B plugs and this fixed my issue. I also replaced the front O2 sensors in the midst of troubleshooting my troubles. I had rough and misfiring issues with the fake plugs. I checked and tightened the entire intake tract and secured all vacuum hosing with fresh clamps to eliminate and vacuum leaks. The fake plugs were confirmed by the fact that the writing could easily be scraped off. The real Denso plugs do not let the lettering scrape off, the letters are under the glaze on the insulator. The fake plug issue is widespread on the web.

12-10-2020, 08:03 AM	#2 (permalink)
Corsairprime Base Member Join Date: May 2014 Location: Frisco, TX Posts: 215 Drives: 14 370Z Nismo GM 6MT Rep Power: 3546	My P0171 and P0174 problem was caused by fake Denso Iridium FXE24HR11 spark plugs. The electrodes on all of these fake plugs had melted to a gap of .075 to .080. I did buy new genuine plugs from NGK, the Laser Iridium DF8H-11B plugs and this fixed my issue. I also replaced the front O2 sensors in the midst of troubleshooting my troubles. I had rough and misfiring issues with the fake plugs. I checked and tightened the entire intake tract and secured all vacuum hosing with fresh clamps to eliminate and vacuum leaks. The fake plugs were confirmed by the fact that the writing could easily be scraped off. The real Denso plugs do not let the lettering scrape off, the letters are under the glaze on the insulator. The fake plug issue is widespread on the web. old guy likes this. __________________ Corsairprime 2014 Nismo #462, GunMetal Grey, GT-R Start Button, AAM S-Line/R-Line intake and S-Line exhaust, Berk HFCs, Osiris Tuned at JoTech

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