The engine runs rough, running down the road

AL MITCHELL2

MEMBER
1992 CHEVROLET CAVALIER
2.2L
4 CYL
2WD
MANUAL
230 MILES

Like it's missing. I checked the plugs, and they are running clean. I had to smog my car and it did not pass was considered gross polluter. So I replaced the fuel injectors. I had it tested it again but still didn't pass wasn't as bad. So I replaced the catalytic converter, the converter is putting out a rotten egg smell. And the engine bucks and jumps not when I accelerate, it accelerates great but it bucks and jumps when I let up on the accelerator. Could it be the fuel pressure regulator?

Tuesday, February 11th, 2020 AT 1:48 PM

2 Replies

SCGRANTURISMO

MECHANIC
4,897 POSTS

Hello,

Is your vehicle's Malfunction Indicator Lamp[MIL] or "check engine" lamp illuminated?

Thanks,
Alex
2CarPros

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Tuesday, February 11th, 2020 AT 3:11 PM

JOETECHPRO

MECHANIC
705 POSTS

Hey AL MITCHELL2,

I would first check for a vacuum leak.

It is very possible you have an issue with the fuel pressure regulator, the vacuum line to the regulator or a general engine vacuum issue. This would cause excessive fuel pressure and the faults you are describing.

Please follow the guide below to rule out an intake vacuum leak problem.

https://www.2carpros.com/articles/how-to-use-an-engine-vacuum-gauge

If you have access to a vacuum gauge you can unplug the hose from the regulator and check the vacuum at idle to the pressure regulator. You should have engine vacuum (18-21"Hg approximate).

You can also apply a vacuum to the port on the pressure regulator and see if it holds with a vacuum pump. If the vacuum leaks of replace the regulator.

Let us know what you get.

Regards, Joe

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Tuesday, February 11th, 2020 AT 3:19 PM