At this point, I feel it is a fuel pressure related issue. The only way to confirm I'm correct is to check fuel pressure after the vehicle sits and would normally have the issue. Here is a link that shows in general how it's done:
https://www.2carpros.com/articles/how-to-check-fuel-system-pressure-and-regulator
Here are the directions specific to your vehicle. You will need a fuel pressure gauge, but most parts stores will lend or rent one to you.
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2000 Honda Civic LX Sedan L4-1590cc 1.6L SOHC MFI
Component Tests and General Diagnostics
Vehicle Powertrain Management Fuel Delivery and Air Induction Fuel Pump Fuel Pressure Testing and Inspection Component Tests and General Diagnostics
COMPONENT TESTS AND GENERAL DIAGNOSTICS
Inspection
1. Relieve fuel pressure.
pic 1
2. Remove the 12 mm banjo bolt from the fuel filter while holding the fuel filter with another wrench. Attach the special tools.
3. Start the engine. Measure the fuel pressure with the engine idling and the vacuum hose of the fuel pressure regulator disconnected from the fuel pressure regulator and pinched. If the engine will not start, turn the ignition switch ON (II), wait for two seconds, turn it off, then back on again and read the fuel pressure.
Pressure should be: except B16A2 engine:
260 - 310 kPa (2.7 - 3.2 kg/Sq.cm, 38 - 46 psi)
B16A2 engine: 270 - 320 kPa (2.8 - 3.3 kg/Sq.cm, 40 - 47 psi)
4. Reconnect vacuum hose to the fuel pressure regulator.
Pressure should be: except B16A2 engine:
200-250 kPa (2.0 - 2.5 kg/Sq.cm, 28 - 36 psi)
B16A2 engine: 210 - 260 kPa (2.1 - 2.6 kg/Sq.cm, 30 - 37 psi)
If the fuel pressure is not as specified, first check the fuel pump. If the fuel pump is OK, check the following:
- If the fuel pressure is higher than specified, inspect for:
- Pinched or clogged fuel return hose or line.
- Faulty fuel pressure regulator.
- If the fuel pressure is lower than specified, inspect for:
- Clogged fuel filter.
- Faulty fuel pressure regulator.
- Fuel line leakage.
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Let me know what you find or if you have other questions.
Take care,
Joe
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Saturday, August 8th, 2020 AT 9:42 PM