2000 gmc yukon xl 5.3,
Sound like a misfire problem, may be as simple as cleaning the water or gunk out of
the gas tank which is what I always do 1st because it's easy and
inexpensive. If your fuel is contaminated with gunk, grime, water and/or bottom junk like rust this will cause stalling, sputter, lost power in acceleration, etc. Scanned the PCM to know if some fault code is stored there.
Also, to get an accurate assessment of the fuel pressure, you will have to install a fuel pressure gauge. Fuel pressure should be 60-66 psi at the fuel rail.
If the pressure is too low, the engine will not start and fuel pump
replacement will be necessary. It sounds to me as if you have a bad
fuel pump.
Additionally, I sugggest read this TSB info: Light Throttle Hesitation or Misfire - keywords 4.3 5.0 5.7 accelerate backfire buck chuggle code decelerate detonation DTC hard harsh hot injector L30 L31 L35 launch miss noise surge #PIP3470 - (Jun 16, 2005)
Light Throttle Hesitation or Misfire
1996-2000 Chevrolet Astro, Blazer, C Pickup, Express, S10, Silverado, Suburban, Tahoe
1996-2000 GMC C Pickup, Jimmy, Safari, Savana, Sierra, Sonoma
1996-1999 GMC Suburban
1996-1999 GMC Yukon
The following diagnosis might be helpful if the vehicle exhibits the symptom(s) described in this PI.
Condition/Concern: The customer concern may be a miss, buck, or fishbite type feeling on a deceleration.
* This condition can usually be duplicated just after a smooth gradual acceleration, cresting a hill, or just after the TCC engages.
* This condition will not occur on a cold engine, it becomes more evident at normal operating temperature.
* A rough idle or poor idle quality may also be noticed.
* Scan data may look normal with only random misfires showing up in misfire data.
* This condition will vary in intensity from just a light bump to a severe buck. The bump or buck caused by this condition can induce a driveline clunk or ringing of the propshaft. The driveline clunk or ringing may be misinterpreted as a transmission or driveline concern.
* This condition is similar to, but far more harsh than the miss/buck/surge created when the CMP offset is set incorrectly.
Recommendation/Instructions:
* Question the customer and verify if there has been any previous repairs made to the vehicle that may have allowed the improper installation of the injectors.
* Use the Tech 2 and verify the CMP ****** is set correctly. Use the current SI procedures for Camshaft ****** Offset Adjustment and adjust as needed.
* If the SI procedures have been completed for the vehicle symptom duplicated, and the diagnostics are inconclusive, it is possible that the SCPI / CPI injector nozzle(s) are not in the proper cylinder location. There is no apparent correlation between the number of improper nozzle locations and the severity of condition.
* If improper injector installation is suspected, remove the Upper Intake Manifold and inspect the injector positions. The engine cylinder numbers are molded into the Injector Fuel Metering Block. Verify the individual cylinder injector poppet positions correspond with the engine cylinder numbers marked on the Fuel Metering Block. Evaluate the customer concern after the injectors are installed into the proper cylinders.
Please follow this diagnostic or repair process thoroughly and complete each step. If the condition exhibited is resolved without completing every step, the remaining steps do not need to be performed.
GM bulletins are intended for use by professional technicians, NOT a "do-it-yourselfer". They are written to inform these technicians of conditions that may occur on some vehicles, or to provide information that could assist in the proper service of a vehicle. Properly trained technicians have the equipment, tools, safety instructions, and know-how to do a job properly and safely. If a condition is described, DO NOT assume that the bulletin applies to your vehicle, or that your vehicle will have that condition. See your GM dealer for information on whether your vehicle may benefit from the information.
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