I have a 2001 Disco 2 and i have been having a random misfire problem for a while. I have O2 sensor Bank 1 Sensor 1 code. Is it possible that the O2 sensors could make my vehicle misfire? I have replaced coils, i have repaired any possible intake leaks, i have checked spark plugs. Im at a loss . Help please.

 

ignition wires?

 

yes i replaced them to

 

If you have new coils, plugs, and wires and have canvassed for vacuum leaks (replacing plenum gasket and checking for any leaks elsewhere) then the only other common cause (aside from head gaskets and compression problems) is the MAF. I've swapped my MAF for a good one on advice here despite no MAF code and the misfires instantly disappeared.

Have you done a smoke test to check for leaks? What cylinders are misfiring? Do you have any other codes?

 

Hi thank you sir... I didn't do smoke test but I am going to change maf sensor and plugs but I did look at the plugs they were firing special number 5& 8

 

You can also just swap the plugs from good cylinders to bad and see if the misfire follows. If so, it is those plugs.

 

How to smoke test?

 

I pull the air intake off and put a surgical glove over it and then get a small hose to fit that capped fitting on the passenger side of the intake. It is below the two top hoses. Then I smoke a cigar and blow the smoke in the hose until the glove inflates or I can't take it anymore. The smoke comes out somewhere. That's the theory anyway. It is best done at night with a flashlight so you can find where the smoke is escaping.

 

D2s in CO may be happier.
......

 

And their owners! And vendors of snacks that are open after midnight!