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Not dying yet, but...our 2001 Yukon XL Service engine light has been on. It most recently went to the dealership and 2 codes were found. One was for the EGR system and the other was a fuel circuit short. EGR was staying closed when should be open. Fuel circuit short was fuel pump relay shorts to ground. The techs looked over the system, found no hard problems, drove for weekend, re-flashed computer (re-boot), and returned the vehicle with no witnessed problems.
Sure enough, 12 hrs later the light comes back on. GM tech is "at a loss." It goes back in for another round of diagnostics tomorrow, but they said the next step is to call GM tech engineer.
As for symptoms, the vehicle hesitates (starves for fuel) after accelerating to city driving speed (40mph). We've also started noticing it on the highway. In either case, it seems to be as we are coming out of the throttle (backing off). It's not an "always" thing. It's intermittent.
Any suggestions?
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