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Q: weird noise with cold air intake and idle

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I recently installed a cold air intake and everytime i drive it and get to about 1200-1800 rpms the car makes a weird metal noise, sounds like somethings loose also it sounds like metal scraping. And also one other thing is sometimes when the car is warmed up and i turn it on the rpm needle goes up and down and up and down then gently goes below 1k rpms.. It keeps idling high and whats weird is it goes up and down about 4 times. Like major ups and down. Any advice would be nice thanks

My car has 35000 miles.
My car has an automatic transmission.

A: This is a common symptom of the mass air fl...

This is a common symptom of the mass air flow sensor needing to be upgraded due to the increased air intake. The mass air flow sensor operates based upon predetermined stock tuning in the ECM. When the air flow changes, this can cause the jumping in RPM's due to the imbalanced air/fuel mixture being created by increasing the air flow. I would recommend having an expert from YourMechanic come to your home to diagnose and replace your mass air flow sensor.

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