Misfire

Tiny
SHAWN.GOULET-97
  • MEMBER
  • 2004 OLDSMOBILE ALERO
  • 3.4L
  • V6
  • 2WD
  • 163,822,029 MILES
I removed the Intake manifold and used and air compressor to try and clean out the manifold and my intake. After doing this once the car gets warm and I am idling it begins to idle so rough it shakes the car, I lose all my power, my fuel mileage goes to crap and after I reach 30 mph the check engine light blinks at me. I can change the spark plug and its good for about fifteen minutes then back to running pour. I changed the spark plugs and wires. New gaskets. I am out of options and beginning to get very frustrating. I regret taking it apart to begin with because it was running good before I figured it might be good for it, obviously not.
Friday, September 7th, 2018 AT 8:28 PM

5 Replies

Tiny
ASEMASTER6371
  • MECHANIC
  • 52,797 POSTS
Good morning.

Did you remove the upper manifold or the lower intake?

Did you remove the injector rail with all the injectors? It may be that dirt got into the injectors and they are not sealing correctly causing a rich running condition.

Roy
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Saturday, September 8th, 2018 AT 5:35 AM
Tiny
SHAWN.GOULET-97
  • MEMBER
  • 4 POSTS
Upper manifold. Did not remove fuel rail, but a buddy of mine told me when I push the little bleed thing on the rail gas should squirt out with a lot of pressure. Well I do that and gas slowly leaks out.
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Saturday, September 8th, 2018 AT 3:50 PM
Tiny
ASEMASTER6371
  • MECHANIC
  • 52,797 POSTS
Okay, you need to get a fuel pressure gauge and measure the pressure.

(Key ON, Engine OFF) 358-405 kPa (52-59 psi)

Roy
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Saturday, September 8th, 2018 AT 4:02 PM
Tiny
SHAWN.GOULET-97
  • MEMBER
  • 4 POSTS
What happens if the pressure is not correct?
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Saturday, September 8th, 2018 AT 5:10 PM
Tiny
ASEMASTER6371
  • MECHANIC
  • 52,797 POSTS
The fuel pump will have to be replaced.

Roy

https://www.2carpros.com/articles/how-to-replace-an-electric-fuel-pump
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Sunday, September 9th, 2018 AT 10:10 AM

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