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High-pitched whistling at light throttle on the freeway

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YOUR RESEARCHHigh-pitched whistling at light throttle on the freeway

Leading reported evidence

Replace upper and lower intake manifold gaskets as well

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No successful repair reported for this finding.

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Unsuccessful attempts: 1
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Performed · outcome unconfirmed · Original poster
I just changed upper and lower intake manifold gaskets as well, but nothing I did had an effect on the sound.
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High-pitched whistling at light throttle on the freeway

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Leading evidence: 'Replace upper and lower intake manifold gaskets as well' (no explicit attributable resolution; this is a reported action or suggestion). Across 1 matching discussions, The most frequently discussed action is 'Replace upper and lower intake manifold gaskets as well' (1 discussions). For that action, 0 discussions report a resolution and 0 report an unsuccessful attempt. No action has an explicit, attributable resolution report under the current rules. These are forum reports and suggestions, not a confirmed diagnosis.

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Frequently discussed actions (1)

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Replace upper and lower intake manifold gaskets as well

No successful repair reported for this finding.

0
Reported fixes: 0
Unsuccessful attempts: 1
Discussions

Read evidence and context

Discussions that performed work without a confirmed outcome: 1

0 original-poster resolution reports. Counts can overlap; they are not unique people or a success rate.

0 discussions have direct query context; 0 report a fix in that context. Other evidence may inherit the discussion’s subject.

Performed · outcome unconfirmed · Original poster
I just changed upper and lower intake manifold gaskets as well, but nothing I did had an effect on the sound.
Original post Read captured discussion
High-pitched whistling at light throttle on the freeway

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Counts describe captured discussions, not unique people or a diagnosis. Author identities are not reliably stored. Exact duplicate evidence is counted once across matching discussions; one discussion counts at most once per action/state. Multiple repairs reported together remain a combination. Suggestions and failed attempts do not establish a fix. Matches cover whole discussions and can include related faults, model variants and incomplete threads.

4 eligible posts · 0 unverified posts · 1 discussions match the subject in their title or opening post.

Rennlist: 1 discussions

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Generation: 20261027T035758Z · outcome-qualification-6. Deterministic extraction; no AI model inference. How we use sources

POST 1 / ORIGINAL POSTEROriginal post

Hey gang. Got another one for you that's plagued my 03 C2 coupe 6mt since I bought it. When I'm driving on the freeway at light throttle, usually in top gear I get a persistent high-pitched whistle sound. It comes and goes with throttle so I assume it's some kind of leak somewhere. Normally I'd have guessed AOS but my entire system is new with a UAOS and upgraded crossover hose. I just changed upper and lower intake manifold gaskets as well, but nothing I did had an effect on the sound. The car runs awesome, so this is really more of an annoyance than anything else, but if you have suggestions, let me know. I'll try and get video next time I have my wife riding with me.

POST 2Original post

Top of mind would be the vent near the fuel filler. You can rule it out with tape or chewing gum.

POST 3 / ORIGINAL POSTEROriginal post

It sounds more like it's coming from the rear of the car, but I'll try this out just to rule it out. Thanks for the suggestion!

POST 4Original post

From the rear of the car and related to throttle input? Try another intake leak. Doesn�t necessarily have to be from the gaskets you just replaced. Do you have a buddy with a smoke machine? That is the best way to find these leaks.

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