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Ask GM Tech (Cam) Your Own Question
GM Tech (Cam)
GM Tech (Cam), Chevy Technician
Category: Chevy
Satisfied Customers: 29588
Experience:  GM Grand Master Technician 2007. 14 years experience.
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I have A 2002 CHEVY AVALANCHE 5.3 with 30,000 original mile.

Customer Question

I have A 2002 CHEVY AVALANCHE 5.3 with 30,000 original mile . when the engine is cold acceleration is very poor and slow no matter how much pressure on gas pedal until it warms up and then great .there are no codes, and does not misfire , map has been cleaned .fuel filter has been changed as well as air filter ,thanks ,mike
Submitted: 11 months ago.
Category: Chevy
Expert:  GM Tech (Cam) replied 11 months ago.

Mike, I am Cam.
I have a couple questions regarding this.

First does it lack power at any time after it is warmed up?
Does it do this after every start or just the first start of the day?

Customer: replied 11 months ago.
once it is warmed up ,lots of power after every start
just when cold
Expert:  GM Tech (Cam) replied 11 months ago.

Ok, so my first thought is a faulty sensor, but which one might be hard to find.
- the engine coolant sensor in the drivers side cylinder head.

-intake air temperature sensor as part of the mass air flow sensor.
- possibly a bad ground under the vehicle, drivers side under the drivers door on the frame.
-possibly a bad connection or even a module but I would keep this as a last option.

My steps would be to watch the data on the scanner, see if one sensor is reading out of spec and change the faulty one.
Check the fuel pressure to ensure its properly responding at all times.
Check fuel pressure regulator.
Check and possibly change the crankshaft position sensor as it can be a cause of this.
If nothing else, change the engine computer, but again, this would be if all else checks out good.

Customer: replied 11 months ago.
hi .when I did a code scan I did get code c0265 ,ABS thought it did not apPear on the dash .I wouder if the ground you mentioned above is the same ground as the EBCM .MIKE
Expert:  GM Tech (Cam) replied 11 months ago.

That code is for the pump motor relay, which is integral to the module.
Yes the ground is the same as there.

Customer: replied 11 months ago.
Could this indicate that poor ground may be causing poor acceleration when cold, thanks mike
Expert:  GM Tech (Cam) replied 11 months ago.

Thats one of my thoughts Mike, the other as I mentioned are skewed sensors.