Thread: 98 GMC Suburban - Multiple O2 codes/hard starting
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Old 12-20-2008, 09:42 AM
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Re: 98 GMC Suburban - Multiple O2 codes/hard starting
It's unlikely a vacuum leak would give symptoms like you're experiencing. GM does not publish ANY engine running fuel pressure specs, for this system. What is the pressure and leakdown rate when the engine of off? Ignition on, engine off, and the fuel pump running. Should be 60psi to 66psi and remain above 55psi for 3 to 5 minutes after the fuel pump shuts off. Make sure the fuel filter is not restricted.
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