Just as it is impossible to say what it is (from a far), it is impossible to say what it isn't. But for practical purposes I would say it absolutely it isn't the cold start valve, the temp sender, or the fuel pressure regulator.

Some statistical analysis and theoretical concept would tell me that. A scope could confirm it but a statistical approach would send me looking at plug wire ends. Possibly a leaking or restricted injector/s.

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Steve Brotherton
Continental Imports
Gainesville FL
Bosch Master, ASE Master, L1
33 years MB technician