2005 Chevy Astro ENGINE STUMBLES OR HESITATES

Tiny
MARTY809
  • MEMBER
  • 2005 CHEVROLET ASTRO
  • 6 CYL
  • 2WD
  • AUTOMATIC
  • 88,000 MILES
I HAVE REPLACED THE PLUGS, PLUG WIRES, DISTRIBUTOR CAP, ROTOR, TPS SWITCH, GAS FILTER, O2 SENSOR THE DOWNSTREAM ONE, AND THE TEMPERATURE SENSOR IN THE HEAD. I HAVE SWITCHED THE 93 OCTANE SUNOCO GAS TOO. WHEN I START UP IN THE MORNING, ENGINE IS COLD. IT IS OK AFTER ABOUT 5 MINUTES OF DRIVING AND IDLELING. THEN I TRY TO LIGHTLY ACCELERATE AND THE ENGINE STUMBLES IT IS LIKE IT IS MISSING. THE CHECK ENGINE LIGHT DOES NOT COME ON.
WHAT ELSE COULD BE THE PROBLEM. IT SOUND LIKE THERE IS SOMTHING CAUSING THE MIXTURE TO BE TOO LEAN.
BOB
Wednesday, September 9th, 2009 AT 9:10 PM

3 Replies

Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 108,192 POSTS
When you say lean, it makes me want to tell you to check for vacuum leaks. Have you? Also, have you checked fuel pump pressure? If not, do so. Here is a how to:

https://www.2carpros.com/how_to/how_to_check_fuel_pressure.htm

You will need a gauge, but most parts stores will lend or rent them.

Let me know what you find.
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Wednesday, September 9th, 2009 AT 10:43 PM
Tiny
MARTY809
  • MEMBER
  • 2 POSTS
YES I CHECKED THE FUEL PRESSURE IT IS 61PSI THEN GOES TO 58-59 PSI. VACUUM IS GOOD ABOUT 20 INCHES OF VACUUM.

ANYTHING ELSE.
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Thursday, September 10th, 2009 AT 8:12 PM
Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 108,192 POSTS
Have you checked the EGR valve?
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Thursday, September 10th, 2009 AT 9:00 PM

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