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1998 Chevy Tahoe P0308 and P0161 Codes: Diagnosis and Fix for Cylinder Misfire and O2 Sensor Heater Issue

Model: 98 Chevy Tahoe Fault Code: P0161 Posted: 2008-12-10 11:44

I own a 1998 Chevrolet Tahoe with approximately 125,000 miles on the odometer. It's equipped with a 350 TBI engine and an automatic transmission. About three weeks ago, the vehicle began running roughly, and the Service Engine Soon (SES) light came on—frequently blinking. I took it to AutoZone for diagnostic testing, which revealed two trouble codes: - P0308: Cylinder misfire detected — Cylinder 8 - P0161: Heated Oxygen Sensor (HO2S) Bank 2 Sensor 2 — Heater circuit malfunction Possible causes listed by the technician include: - Ignition system faults (spark plugs, ignition wires, coil) - Vacuum leak - Fuel injector failure - Abnormal fuel pressure (too high or too low) For P0161 specifically: - Defective oxygen sensor - Poor electrical connection at the sensor - Faulty circuit fuse About a year ago, the truck exhibited similar symptoms. A distributor drive gear issue was identified and repaired. Prior to that, I replaced the distributor cap, rotor, spark plugs, and ignition wires myself. I'm seeking advice on how to properly diagnose and resolve these issues—especially since the vehicle is aging and may have multiple underlying problems. Any guidance would be greatly appreciated. Thank you, Danny

Related fault codes
P0161P0308
Comments (6)
Anonymous 2008-12-11 06:53

Did you install OEM or original equipment manufacturer (OEM) parts? GM has known compatibility issues with aftermarket components. Confirm that cylinder #8 is receiving a spark, then systematically evaluate other potential misfire causes and address the O2 sensor heater circuit issue. Good luck—please update us on your progress.

Anonymous 2008-12-11 11:25

No, I did not use AC Delco or any OEM parts. The truck has run smoothly for about one year (4,000 miles) after using the AutoZone components. I plan to remove and test the spark plug from cylinder #8 to verify if it is firing properly.

Anonymous 2009-01-09 06:17

I'm quite pessimistic—this vehicle is a backup for me, so I delayed repairs out of fear that it would be expensive. I thought it was something serious and waited until after Christmas. This morning, I opened the hood and discovered that the spark plug wire for cylinder #8 had come loose. Now everything runs fine—I feel like a complete fool for not checking it sooner. Wasn't it always simple? LOL. Danny

Anonymous 2009-01-09 08:33

Yes, we've all been there. Sometimes even a blind squirrel finds a nut! But what about the P0161 code—could that be contributing to the misfire or engine performance issues?

Anonymous 2011-02-07 13:32

Mohawkmtrs wrote: Yes, we've all been there. Sometimes even a blind squirrel finds a nut! But what about the P0161 code—could that be contributing to the misfire or engine performance issues? I'm currently researching information on P0161 for my recently acquired 1998 Tahoe. The vehicle is in need of maintenance, and this code seems central to its operation. I’m planning a long drive to Lake Tahoe—a significant journey—but I’d like to ensure reliability before departure. Any insights or recommendations would be helpful.

Anonymous 2011-02-08 07:06

P0161 indicates a heater circuit malfunction in the oxygen sensor (Bank 2, Sensor 2)—located on the passenger side behind the catalytic converter. Given the vehicle's age and mileage, this sensor is likely worn out and needs replacement. For best compatibility and performance, install a new OEM sensor from an authorized dealership—avoid aftermarket alternatives.