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Showing results for tags 'o2 sensor'.
I recently bought a 1990 Jeep YJ with 4 cyl 2.5 TBI engine. The jeep runs great except during warm-up. It starts fine and runs and idles well initially. As soon as the temperature gauge begins to climb off the 100 degree mark, the engine begins hunting and surging and usually stalls. If I push down on the accelerator and run it to 1000+ rpm, I can get the engine to heat up to operating temperature. At that point (~160-170F) the idle becomes stable again. So far I haven't done a lot of troubleshooting but have checked the EGR valve, changed rotor/cap, air filter, and fuel filter with no success. I'm wondering if it might be a bad O2 sensor that's slow to heat up which will be the next thing I check/replace. Any ideas or help is much appreciated!