Mechanics

Z71, MISS FIRING

2007 Chevrolet Tahoe • V8 4WD Automatic • 97,997 miles

Hello, I purchased a used 2007 Tahoe Z71 and it's been miss firing (missing) 2 wks after my purchase. The check engine came on so I had it serviced: new axles, fuel system cleaning and another week later they had to replace the fuel pump. The techs say my spark plugs are good, but after all this my tahoe still misses while stopped. It does have 97k miles, use to be a fleet. Any idea? Thank you in advance.
Avatar
Maeday77
August 19, 2011.



What are the exact code numbers being set when the check engine light comes on?

Wrenchtech
Aug 19, 2011.
P0171 and P0172. Prior to replacing the fuel tank it was putting out 48PSI. That has been corrected, but it's still missing. There is no chk engine light on currently.

Tiny
Maeday77
Aug 19, 2011.
I think you meant PO171 and PO174.
What is the fuel pressure now?

Wrenchtech
Aug 19, 2011.
Yes, PO. It's now at 65PSI now.

Tiny
Maeday77
Aug 20, 2011.
You should be getting some misfire codes if it's still missing.

Wrenchtech
Aug 20, 2011.
That's what's baffling, it is not giving us any other codes. Well thanks for trying.

Tiny
Maeday77
Aug 20, 2011.