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Category: Vauxhall
Satisfied Customers: 1192
Experience:  Vauxhall diagnostic technician
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vectra 2.2 direct Z22YH - misfire at 5,000 RPM - no MIL on

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vectra 2.2 direct Z22YH - misfire at 5,000 RPM - no MIL on and misfire disappears until engine stopped then re-started then it it misfires again.

PS - fitted Denso IK20 iridium plugs 2 years ago gapped at 0.8mm ans all has been well until now.

Welcome to just answer,

This type of misfire is usually due to fuel pressure fluctuations and is a very common fault.

It usually leaves a fault code but that depends on the type of scanner used, the recommended repair is to replace the high pressure petrol pump and regulator, this was such a common fault that it featured on BBC watchdog program.

I hope this helps, best regards, Vauxdoc.
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