I'm diagnosing a rough running/starting 2007 Blast. Replaced the manifold coupling as a start as it's a typical culprit I understand. Onlt 1200 miles tho but starting there. When I took the air cover off I did notice only three allen head bolts holding the air box onto the carb. Should there be four? There's a hole for one but it's empty. I never removed it. Only owner - I did all the service.

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BTW the new coupler did help maybe 20%. Next is fuel filter and plug.

Scott
Capital District, NY