Hi,

 

Have recently developed an intermittent misfire on 'low revs' (around 1500 - 2000 mainly) and this when going 'light' on accelerator. If I floor it (or just have a bit of heavy right foot), then there is no misfire at all. I also get a bit of 'splutter' and the odd 'light back fire' when going off accelerator and decelerate (again this mainly happen when revs pass around 1500 - 2000). Car is a manual NA.

 

Spent a bit of time looking into this today, and have determined that it is the 'left bank' (even cylinders) that has the misfire (can hear clearly that it is in left exhaust - right sounds perfect). Cleaned out injector, coil pack and ECU temp sensor connectors, but has not made any difference.

 

Checked injector resistance and injector 6 (left bank - rear) have a reading of 14.7 ohm, which is a little bit higher then the rest (they are 12 - 12.8 ohm). Have replaced injector 3 and 4 before and when they went the reading was 80 - 120 ohm (from memory - I know it was much higher then around 12 ohm that I understand is what we should have).

 

I suspect (guess) that injector 6 is on way out, but is 14.7 ohm 'high enough' for it to cause misfire ?

sounds like O2 sensors

Injector range is 10-14ohms, so is out of spec, to eliminate the O2 sensors, disconnect them and the ECU will run on a means setting.

Will try the O2 sensor as soon as I get time in next few days (should probably run a ECU Diagnostic as well - to see if I have any code).

 

Where is the easiest place to disconnect sensor ?

Disconnected the O2 sensor this evening, and misfire is gone. Car drive the way it used to, so will look at getting new sensors ordered / arranged.

 

Believe that Bosch was the supplier to Nissan, and that sensor 13091 would be the 'correct' fit.

 

From what I understand there is no risk for damage to drive car with O2 sensor disconnected for a shorter period.

Disconnected the O2 sensor this evening, and misfire is gone. Car drive the way it used to, so will look at getting new sensors ordered / arranged.

 

Believe that Bosch was the supplier to Nissan, and that sensor 13091 would be the 'correct' fit.

 

From what I understand there is no risk for damage to drive car with O2 sensor disconnected for a shorter period.

 

 

 

No need to rush to get new 02 sensors, most owners just leave them disconnected even ok at MOT time.

 

Jeff TT

Thanks for info. That is good to know. Probably leave it until after the summer season then.