Check Engine Light

[95Finder]

I just got my 1995 Pathfinder on the road after replacing the alternator and front pads/rotors. The Pathfinder was sitting for about 6 months with the gas tank almost empty. I think condensation formed and some sh*it got in the fuel filter. I am going to change the fuel filter and put dry gas in for the next few fill ups but why would the check engine light go on and off. It isn't too often but every now and then it lights up and then goes out about 1 second later. Also it smells like sulfur after the car has been running for a bit. Will the codes still be in the ecu if the light is flashing on and off intermittently? Any ideas thanks.

[Mr. Pickles]

Try running the codes, its super super easy. Just read the following.

 

Mr Jim saves the day again

[95Finder]

I checked the codes and got code 33 for the oxygen sensor. Could this cause the problems I posted above? Thanks.

[Mr. Pickles]

I checked the codes and got code 33 for the oxygen sensor. Could this cause the problems I posted above? Thanks.

Word is that the O2 sensor can make you truck do all sorts of crazy stuff. The sulfur smell could also indicate a crapped out catylitic converter.

[88pathoffroad]

Yep. If the O2 sensor were indicating a lean mixture, the ECU would compensate by injecting more fuel, causing an overly rich condition and making the catalytic converter output smell like hydrogen sulfide from the unconverted hydrocarbons in the overly rich exhaust.

[Mr. Pickles]

Yep. If the O2 sensor were indicating a lean mixture, the ECU would compensate by injecting more fuel, causing an overly rich condition and making the catalytic converter output smell like hydrogen sulfide from the unconverted hydrocarbons in the overly rich exhaust.

Go on with your bad self, Mr. Wizard.