I have a 97 s-10 pickup with a 4.3 vortec engine. While driving around town, my truck started to hesitate and then died. It wouldn’t start until about a half hour of waiting. The outside temperature was about 95-100 degrees. The engine light would go on when it started to hesitate. The more gas I gave it, the more it tried to die. I scanned it with an OBD 11 code reader and it gave me 2 codes, P0131 (O2 sensor circuit low voltage bank 1 sensor 1) and P0151 (O2 sensor circuit low voltage bank 2 sensor 1). The truck has new plugs/wires, new cap/rotor, new fuel filter, new air filter. Any ideas as to what the problem may be?
If you believe the O2 sensor codes, the exhaust is lean. The first thing I would look at is the fuel pump pressure, especially when the problem is happening. I suspect you may have a fuel pump that is dying.
I replaced my fuel pump less than a year ago.
Darn – that seemed such a likely candidate. Still check the fuel pressure, could be something else, maybe fuel pressure regulator. Also look at the igniter. These become flaky when they fail. Also suspect the coil or high voltage arcing somewhere. If you can get it into a nonstart condition, check for spark to narrow down your search pattern.