Intermittent rough idle/no start

1997 HONDA CIVIC

172,000 MILES • 4 CYL • 2WD • AUTOMATIC

HONDAMIKE

✓Experienced Mechanic
71 POSTS

After being warm, car would not start. Acted like it was flooded. Held down the throttle, it sputtered to life and started running.
It happened again and thought since it was hot outside, the igniter was going... so I replaced it.
Test drive, all okay...
Next time, hard start again...
Rough idle...
I removed the vacuum line to the fuel regulator and it runs great! Which is weird because a vacuum leak usually makes an engine run rough?

Do I have a bad fuel regulator?

Thanks!

Jul 12, 2021 at 10:00 AM

ASEMASTER6371

✓Experienced Mechanic
52,796 POSTS

Good morning,

When you removed the hose, you raised the fuel pressure. By doing that, the engine runs better.

This sounds like you have a bad fuel pump not producing the correct pressure. You need to test the pressure to confirm. You can rent a tester from a parts store.

https://www.2carpros.com/articles/how-to-check-fuel-system-pressure-and-regulator

https://www.2carpros.com/articles/how-to-replace-an-electric-fuel-pump

Roy

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Jul 12, 2021 at 9:02 PM

HONDAMIKE

✓Experienced Mechanic
71 POSTS

Thank you. I will do that.

Jul 12, 2021 at 11:52 PM

ASEMASTER6371

✓Experienced Mechanic
52,796 POSTS

You are welcome.

Always glad to help.

Roy

Jul 14, 2021 at 8:35 AM

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