Vac Leak/Missfire

[Shipe12]

Hi i have a 99 GST and i have a random multiple missfire code i have replaced everything but the coil packs. In the diagnostics it says you could have a vaccum leak thats causing the missfire. Could a missfire cause the car to run at a lower In Hg or do i have a vaccum leak for sure, because my car idles at 10-15 In hg. thanks for any help.

 

[habitatguy187]

Usually when your vac at idle is that low you have a vacuum leak. Do a boost leak test with soapy water and let us know what happens.

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