2000 Buick Park Avenue Ultra Stalling & Codes P0131, P0336, P0137: Causes, Diagnosis & Fixes
HELP REQUESTED: I own a 2000 Buick Park Avenue Ultra and have been experiencing intermittent stalling and rough idle since last week. After replacing spark plugs, wires, crankshaft position sensor (CPS), alternator, fuel pump, fuel filter, upstream O2 sensor, and idle air control valve, the issue persists. The car now shows a pattern: every morning for three days, it struggles to start — it cranks repeatedly with a low growl sound, as if struggling to turn over. Once it finally starts, it runs with a hard idle, nearly stalling unless I keep the throttle steady. For a few minutes during warm-up, a small portion of the catalytic converter turns red and emits a rattling noise, followed by the check engine light turning on. After warming up, the car runs smoothly without any issues, and the check engine light cycles off. However, today's diagnostic scan revealed codes P0131 (Low Oxygen Sensor Voltage Bank 1 Sensor 1), P0336 (Crankshaft Position Sensor A - Wrong Position), and a history of P0137 (O2 Sensor Bank 1 Sensor 2). The P0336 code appears multiple times in the past. I'm wondering if the issue lies with the crankshaft position sensor — I only replaced one part, not both. Could leaky fuel injectors be causing temporary startup issues due to fuel puddles burning off during cold starts? What other diagnostics should I perform? Any insights or troubleshooting steps would be greatly appreciated.
With your OBD2 scanner, perform a crankshaft position (CKP) relearn and monitor B1S1 and B1S2 sensor voltages. A common swag is low fuel pressure — use a fuel pressure gauge to verify this before proceeding. Ensure the relearn process is complete after any sensor replacement.