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Q: I have an aftermarket intake and it's reading 4.9 psi. Is that good or bad?

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Aftermarket intake

My car has 171000 miles.
My car has an automatic transmission.

Hi there. An intake manifold should read 19 to 22 hg. This is 19 vacuum to 22 vacuum. If you are getting a psi reading, then there is either a turbo on your vehicle or the engine timing is out of sequence. Recheck with your gauge to determine what you are seeing. If you meant to say 4.9 hg (vacuum), then check the bolts to see if they are tight. Then check the gasket and make sure that its secured on all of the ports to the engine. If you need further assistance with a major vacuum leak, then seek out a professional, such as one from Your Mechanic, to help you.

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