| (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. |
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
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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.
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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.
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When the computer thinks the engine is lean, it adds more fuel. This can make the engine run rich and trigger the light.
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Common symptoms:
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Light comes on after a few minutes of driving
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Weak acceleration
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Ticking or puffing noise at the manifold
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Rough idle
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Strong exhaust smell
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Poor fuel economy
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Yes, the manifold leak can cause the O2 sensor code and the check engine light.
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Best order to fix:
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Fix the exhaust manifold gasket leak
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Clear the codes
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Test drive
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Replace the O2 sensor only if the code returns
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