1997 Chevy Suburban stutter on acceleration

Tiny
JIMMY25
  • MEMBER
  • 1997 CHEVROLET SUBURBAN
  • V8
  • 4WD
  • AUTOMATIC
  • 235,000 MILES
The owner has said the problem is intermitant but becoming more frequent.
The engine seems to stutter while accelerating from a stop light. Once the rpms come up it seems ok. It does it more frequent with fuel level below 1/3. The fuel pump seems pretty loud. The pressure reads 52 at idle. When you accelerate either standing still or driving, it moves up to 60 psi momentarily and drops back to 52. If you let off the throttle it drops to 52 right away. The book says it should be 60 to 66. Is there a fudge factor? Or absolutely not, 60 to 66 is where it has to be. I have used two different gages and both read the same. I changed the fuel filter and rechecked pressure. No difference.
At one point I was able to get it to stumble while in neutral. The gage was at a fairly steady 52 psi.
I also removed the EGR valve to check for obstacles. It looked ok.
It is a 5.7L CSFI.
The intake manifold was very recently resealed due to a coolant leak at the drivers side front coolant cross-over. It has not changed the stutter issue
Any suggestions?
No check engine light.
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Saturday, April 17th, 2010 AT 5:58 PM

5 Replies

Tiny
BMRFIXIT
  • EXPERT
Fuel pressure should be CSI 60-66 or for SFI 56-62
In both system fuel pressure a bit low and if not know but soon fuel pump need to be replaced
Check spark plugs
Spray distributor cap and coil with water and soap mix check for spark leak
Ground a test light and run it at and around the cap, coil, and wires
If have the flat distributor cap almost certain it's at fault
Hook scanner and check distributor and CAM for adjustment
Good luck
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Monday, April 19th, 2010 AT 5:44 AM
Tiny
JIMMY25
  • MEMBER
How often is the fuel regulator the problem? The pressure only seems low, not irratic.
Also it does have the flat cap. If that were it, why would it only do it occasionaly? It goes for long periods where it is just fine. It does act up more after it is been running for a while. I was also going to say that when I changed the fuel filter, I got about 30 1/16" beads of water. Is that about normal?
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Monday, April 19th, 2010 AT 6:46 PM
Tiny
BMRFIXIT
  • EXPERT
We find it very common for the flat cap to fail more often and under load spark will leak and jump around (flat cap is where the wires on the side) use water and soap and spray it use a test light and check coil also using the same method
Shouldn't have any water in the fuel filter check new fuel filter again if have water have to drain and clean tank or do something about it
Fuel regulator is not a common failure that I am aware of
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Monday, April 19th, 2010 AT 7:26 PM
Tiny
JIMMY25
  • MEMBER
I broke down and put the new pump in. The pressure still only reads 52 to 60. What I did notice though, is that prior to replacing the pump, when I would accelerate the engine and turn the key off, most of the time the pressure would drop to 0. After installing the new pump, besides being quiter, it stopped dropping to 0 psi after accelerating and turning the key off. The cap and rotor was ok. I used an otc diag tool and adjusted the distrbutor to 0 on the cam. Seems to run good. Again I appreciate your help. Have a great weekend!
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Thursday, April 22nd, 2010 AT 8:32 PM
Tiny
BMRFIXIT
  • EXPERT
Thank you for the update

Happy driving
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Thursday, April 22nd, 2010 AT 9:21 PM

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