Having problems with your 2002 GMC Yukon Denali ?
Idles rough upon start , goes dead when letting up on gas.
\015 Key switch was left on, the battery went dead. After charging battery the truck now idles rough when started. If you don't touch gas it idles rough and goes dead after letting up on accelerator. When driving truck it goes dead if you let off the gas. We have removed the negative battery terminal in an attempt to reset system, no change.\015
If the bat went dead and was disconnected it can take 25 to 50 miles of driving for computer to reset sensors and controls. Sounds like MAF Sensor maybe reading different than when it was first driven. Did you drastically change climates or altitudes, New readings from when it originally was put into service. Slight changes in temp, alt and other variables gradually reset, if driving does not improve within 50 miles it will need diagnostics.
Based on my own experience, I would guess your fuel pump is dying, which these older Denali's are notorious for. I just had to replace mine, and it's not easy or cheap. Also check the air filter...if it's really dirty/clogged it can effect idle, power, etc.
Repair Help & Product Troubleshooting for 2002 GMC Yukon Denali
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