Intake manifold noise? Help?
05-28-2010, 09:26 PM
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Intake manifold noise? Help? I have a stock '98 T/A. Yesterday I noticed that while at idle when sitting in traffic my engine was acting like it wanted to die, dropping down to 500 rpm or so then jumping back up to normal idle. Today I heard a whirring or whining noise, so I opened up the hood to probe around with a section of rubber hose and there was a loud hissing (air leak) sound coming from right behind the throttle body at the front of the intake manifold. The area of loudest hissing is shown in the red box. This is accompanied by a loud intermittent whirring or whining noise coming from directly below the front of the intake manifold, shown by the yellow arrow. Any idea what is causing this? Any advise as to how I should proceed next? Thanks for your time.
05-29-2010, 11:33 AM
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Sounds like a vacuum leak from that EGR tube. Perhaps the seal has gone bad? I'd try spraying around there with some carb cleaner and see what happens. The seal for that tube is not expensive, so I'd probably just replace it.
05-29-2010, 03:13 PM
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Ok, update. The two noises are unrelated. I figured out the air leak and fixed it, and that solved my low idle problem. Now after the engine is warmed up I'm getting a high pitched whine, seems to be coming from the top part of the timing chain cover. It only does it after the engine is warm and only does it while under 1500 rpms. Any ideas whats causing it?
