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2002 Mazda 626 V6 Engine Shaking with P0133, P1131, and P0305 OBD2 Codes - Diagnosis & Component Locations

Model: 2002 Mazda 626 Fault Code: P0133 Posted: 2007-12-08 21:55

2002 Mazda 626 LV, 2.5L V6, Automatic Transmission, 185,000 miles My 2002 Mazda 620 has been experiencing intermittent shaking, especially when climbing hills. The Check Engine Light (CEL) started flashing today after previously being on for about six months. I retrieved the OBD2 diagnostic codes: P0133 (Oxygen Sensor Bank 1 Sensor 1 Malfunction), P1131 (Oxygen Sensor Bank 1 Sensor 1 Slow Response), and P0305 (Cylinder 5 Misfire). Six months ago, I had the same codes — P0133 and P1131. My dealership sent it to a third-party shop for an O2 sensor replacement, but the issue persisted. A follow-up visit with no resolution led me to stop returning to that shop due to poor service. I've been driving with the CEL on continuously for months without major issues until recently when the shaking became noticeable again. Tonight, the light began flashing. After researching online forums, I’ve gathered some insights: - A user mentioned 'pinging' — a sound similar to rocks in a tin can during startup — which may point to EGR valve issues or a faulty knock sensor. - Based on prior experience with these codes, common fixes include cleaning the MAF sensor, inspecting and cleaning the EGR valve, checking wiring harnesses, and verifying spark plug condition. However, I'm currently unable to locate key components such as the O2 sensors, EGR valve, MAF sensor, or knock sensor. My college's auto technology department has a Mitchell 1 system, but campus is closed until Monday. I’ve already located the front O2 sensor (Bank 1 Sensor 1), which appears clean and well-maintained — though I’m unsure if this resolves the underlying issue. Can anyone provide clear guidance on where to find these components in a 2002 Mazda 626? Are there specific tools or resources recommended for diagnosing P0133, P1131, and P0305? Thanks for your help. My vehicle specifications are listed above.

Related fault codes
P0133P0305P1131
Comments (2)
Anonymous 2007-12-09 13:07

If you're having difficulty locating components without a service manual, it's best to wait until campus reopens on Monday when you can access the Mitchell OnDemand system. When was the last time your vehicle received a tune-up? Consider checking spark plugs and wires — NGK is often recommended for this model. Make sure any replacement parts are of high quality, especially for sensors and ignition components.

Anonymous 2007-12-09 13:28

Mohawkmtrs wrote: If you're having difficulty locating components without a service manual, it's best to wait until campus reopens on Monday when you can access the Mitchell OnDemand system. When was the last time your vehicle received a tune-up? Consider checking spark plugs and wires — NGK is often recommended for this model. Make sure any replacement parts are of high quality, especially for sensors and ignition components. Thanks for the tip! I’ve heard that the Haynes manual for the 626/MX-6/Probe series is outdated and unreliable. I’ll use Mitchell OnDemand at school instead. A fellow forum user recently showed me where the O2 sensor (Bank 1 Sensor 1) is located, as well as how to identify each cylinder in the V6 engine. I’ve owned this car since January 2007 — over 11 months. It originally had 160,000 miles, so I've driven approximately 25,000 miles in that time. That’s a significant mileage increase — likely warrants a full tune-up. I currently use NGK spark plugs and wires, which are widely recommended for this model. Thanks again, Mohawkmtrs!