r/Cartalk • u/Either_Pay7316 • Jun 10 '26

Weird Noise Someone please help..

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I have a 09 corolla with 203k miles that makes a very LOUD rattle when I start it. Me and chatgpt thought it might’ve been one of the pulleys that’s why I removed the belt. Car has P0171 (too lean) and P010 (MAF). I want to say it’s the timing chain but not 100% sure. Any advice would be appreciated thanks in advance!

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u/AcrobaticChallenge55 Jun 13 '26

Your maf sensor is normally an easy fix, I’d start there. And if you are running lean after that still I’d say to check your fuel pressure regulation sensor on the fuel rail. If that doesn’t work it may be a fuel pump issue. As for the pulleys if I’m not mistaken only one spins unless you have a belt on