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Tim West
Tim West, ASE Certified Technician
Category: Cadillac
Satisfied Customers: 4638
Experience:  Ase certified service manager
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99 Cadillac Escalade: bogs down on acceleration..Replaced fuel

Resolved Question:

99 Cadillac Escalade, 105K miles....all computer codes show OK, engine difficult to start, idles fine, but bogs down on acceleration.

Replaced fuel regulator...replaced catalytic converters about 6 months ago.

Any suggestions?
Submitted: 7 years ago.
Category: Cadillac
Expert:  Tim West replied 7 years ago.
Thanks for visiting Just Answer,
This sounds like a fuel pump.
Get some carb cleaner or startng fluid. Spray some into the throttle while cranking. If the extra fuel will help the vehicle start have the fuel pressure checked.
If the fuel pressure is low, replace the pump.
60-66psi is specification.
Customer: replied 7 years ago.

Yes, spraying some carb and choke cleaner into the breather hose near the intake manifold does get it to start.


Pulled the spark plugs yesterday.....ceramic insulators looked almost clean and white.....this would indicate a lean condition.


When the key is turned, the fuel pump whines as it should for a few seconds, and also whines while the engine is running.... indicating that it is working. Even though it is audible, that does not indicate that it is working as it should, delivering the correct volume.


On takeoff, if I baby the throttle, and slowly feather it, the vehicle will come up to speed. But, trying any fast acceleration, either while underway, or from a dead stop, will make the engine knock and sputter, and bog down.


Also, I notice a foul rotten egg smell while driving. I would suspect the catalytic converters, but those were just replaced 6 months ago.


With all this in the fuel pump still a prime suspect? Thanks in advance.

Expert:  Tim West replied 7 years ago.
WEll, a bad rotten egg smell could indicate a clogged cat. I would loosen it and see if the vehicle drives better. A clogged CAT will cause hesitation.

If there is no difference, yes the problem would be the fuel pump isn't producing enough volume (pressure). I usually see fuel pumps failing in this manner. It's rare to see a fuel pump fail and not run at all.
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