Poor fuel mileage after replacing the CAM

EBRAHIM_SS

MEMBER
2007 CHEVROLET CAPRICE
6.0L
V8
2WD
AUTOMATIC
226,000 MILES

My engine has an aftermarket cam, same size as the stock one.
The problem is my car finishes the fuel fast and the engine won’t be stable in engine bay, it moves back and forth with the sound of (sh sh sh sh sh) like it has a big cam, and when the car is in ideal it will burn fuel fast, for example I did fill her up to the max at 16 May 2022, 20 May 2022, the car is empty and I didn’t driven her much. How can I end this problem?

1 Reply

JACOBANDNICKOLAS

MECHANIC
109,867 POSTS

Hi,

If the engine is moving around, it may have a misfire. By chance, does the check engine light stay on while the engine is running? Have you checked fuel pressure to make sure it isn't too high due to a faulty pressure regulator?

If the light is staying on, have the computer scanned for codes. Here is a quick video showing how it's done:

https://youtu.be/b2IJGfImVvw

If you don't own a scanner, most parts stores will do it for you free of charge.

Next, is it possible for you to make a video of the engine running so I can hear and see it? It may help me.

One other question, have you ever noticed smoke from the exhaust? If so, was it blue, black, or white?

Let me know.

Take care,

Joe