I have a 2002 GMC Envoy and it looses power randomly between 1/2 and 1/4 tank full. Can only maintain 25 MPH. If you push on the gas pedal it has no power and will slow down more.
If you fill it up with gas it runs fine. Mostly have problems on the highway at constant speed but is not repeatable and does not happen on every tank full.
Dealer replaced the O2 sensor but still having the same problem. They can't figure it out.
Anyone have this same problem?
Thanks!