My Buick Riviera is Feeling a Little O2 Sensitive (Hunker Junker Chronicles)

(Illustrative Only)

The Gupster Gangsta Mobile
feels a little O2 sensitive
right now so he is going
to get a manifold gasket replaced
 and O2 sensor changed. 

You got to baby a car like this.

I bought a 1985 Buick Riviera—affectionately known as the Gupster Gangster Mobile—for about a thousand bucks. It’s an eight-cylinder beast, and I’ve been tinkering with it myself and sometimes with professional help. I’ve already fixed a few things, including the fuel pump. The check-engine light came on, but it might not actually be the fuel pump causing it as it would sometimes pop on at certain speeds.

Right now I’m having the exhaust manifold gasket replaced and putting in a new O2 sensor. With any luck, that should solve the issue. If it doesn’t, I’ll take it back to the person who installed the fuel pump. Since it’s a mechanical fuel pump, and this car is from the mid-80s, there aren’t many sensors that would trigger a check-engine light anyway. The light only comes on when the engine is warm, and everything else runs fine, so it may be unrelated.

I did some online digging—and got a little help from AI—and that helped narrow things down. Honestly, part of the fun of owning an old car like this is the fixing-up process. I actually own the thing outright: no payments, no stress.

I’ve also been thinking about getting something else down the road—maybe a Land Rover or a Jeep I can wrench on, something with four-wheel drive. A camping van crossed my mind too, but that might give off a “possibly homeless” vibe, so I’m leaning toward the Jeep or Land Rover if I can find the right one.

1985 Buick Riviera – Check Engine Light When Warm, O2 Sensor, Manifold Leak

1. When the engine warms up, the computer switches to closed-loop mode and starts using the O2 sensor. If the O2 signal looks wrong, the check engine light turns on.

2. An exhaust manifold gasket leak before the O2 sensor lets extra outside air into the exhaust. This makes the O2 sensor think the engine is running lean.

3. When the computer thinks the engine is lean, it adds more fuel. This can make the engine run rich and trigger the light.

4. Common symptoms:

   • Light comes on after a few minutes of driving

   • Weak acceleration

   • Ticking or puffing noise at the manifold

   • Rough idle

   • Strong exhaust smell

   • Poor fuel economy

5. Yes, the manifold leak can cause the O2 sensor code and the check engine light.

6. Best order to fix:

   • Fix the exhaust manifold gasket leak

   • Clear the codes

   • Test drive

   • Replace the O2 sensor only if the code returns