1997 E150 has a drivability code of PO135. It means bank one sensor one. Where is the bank one located: after the converter or in the exhaust manifold on which side?
sensor one, is the O2 sensor before the cat (manifold/frontpipe) & relates to the heater inside the sensor. (disregard bank one if it only has one bank of cylinders anyway) check the wiring & multiplug connector & clear codes & see if it re-occurs before replacing it..
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