[eksjay]

Can the 4.0L be driven while a CHECK ENGINE lamp indicating oxygen sensor has illuminated? I have driven it about 300km already with the lamp switching off between starts. It is not currently illuminating. I have read my 95xj has only one sensor whereas the 96 + has two.

Appears to be running fine and not missing a beat, but is it a bad sensor or indicative of an upstream problem?

I have noticed that for a while, my temp gauge is not going up into the 90s (it used to be at least 80 even downhill), except on hot days and in traffic or stopped at lights, tripping the fan at about 105 degrees (normal behaviour) Thermostat was last changed about 8 years ago (genuine part) Could it be that the fuel (ULP 95) is not burning properly? I am not noticing bad fuel economy either.

Should I leave things as they are, or at least change the O2 sensor and see if the check engine warning indicates o2 sensor again? If the warning still appears after a new sensor, does this mean a new thermostat?

I should also mention that a hairline crack is developing in the air inlet manifold (28 yo). Could this be affecting the temp gauge and how the fuel burns? The mechanic had a look at the manifold but did not flag it as a problem - yet.