2003 tahoe how to do a idle speed relearn 5.3

the idle speed is pre set inside the PCM. just operate the car like normal. if idle seems wrong then shut off and start it again. do that about 5 times max should set it.

When ever the engine electrical has been disconnected for a while such as while you are doing some major work on the engine and you disconnect the battery or even if you switch engines the computer will need to relearn the driving habits so to speak. Start the vehicle and let idle for five minutes the put the vehicle in gear and slowly pull out. Drive in a gentle way for 5- 10 miles then slowly you increase the speed. do not just romp into it. It can take several days of normal driving before the computer has relearned the driver information. I take a nice drive through the neighbor hood stopping at stop signs slowly speeding up and slowing down before I go out on the high way. I then take about a 50 mile trip where the speed limits vary from 40 to interstate speed. Once the computer has completed the relearning it will idle and drive smoother for you. Hope this helps.

.idle air control valve,any codes

I already answered this once.

disconnect the battery for a minute or two, that will reset the computer back to default settings and force a relearn to the system, if that doesn't help have the fuel injection system serviced

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You may need to clean inside the throttle body. YouTube has videos on how to do it. Also, your Idle Air Control motor might have carbon build-up in the passage for idle air. Take the motor off, and clean it gently and check the air passage for blockage.

Here is the common problem and fix.

Here are some of the causes of surges, stalls at stops, slow idle speed, erratic idle speed, rough idle and engine hesitation (and other problems), it is in most cases the idle speed control air-bypass valve and or throttle valve and upper intake, these area's get full of gunk and combustion residue over the miles and cause idle issues (stalls, low idle) like yours, Get a can of intake cleaner from any local parts store, not carb spray, intake cleaner, it is made by a company called CRC, remove the air intake hose to the engine, hold the idle high so the engine won't stall, then spray the can of cleaner into the intake while keeping the engine running, use at least 1/2 the can, shut down the engine and disconnect the battery for 5 minutes, then restart and complete a number of mixed driving cycles, town, freeway, stop and go etc., after a few days the problem will go away as the system will relearn to the clean intake.

the idle speed is computer controlled and not adjustable, slow idle is caused by a dirty intake, do the following.

Here are some of the causes of surges, stalls at stops, slow idle speed, erratic idle speed, rough idle and engine hesitation (and other problems), it is in most cases the idle speed control air-bypass valve and or throttle valve and upper intake, these area's get full of gunk and combustion residue over the miles and cause idle issues (stalls, low idle) like yours, Get a can of intake cleaner from any local parts store, not carb spray, intake cleaner, it is made by a company called CRC, remove the air intake hose to the engine, hold the idle high so the engine won't stall, then spray the can of cleaner into the intake while keeping the engine running, use at least 1/2 the can, shut down the engine and disconnect the battery for 5 minutes, then restart and complete a number of mixed driving cycles, town, freeway, stop and go etc., after a few days the problem will go away as the system will relearn to the clean intake.

Try this.
Here is the most common cause of surges and stalls at stops and low erratic idle speed and rough idle, it is the idle speed control air-bypass valve and throttle valve (IAC for short), they get full of gunk over the miles and cause idle issues (stalls, low idle) like yours, Get a can of intake cleaner from any local parts store, not carb spray, intake cleaner, it is made by a company called CRC, remove the air intake hose to the engine, hold the idle high so the engine won't stall, then spray the can of cleaner into the intake while keeping the engine running, use at least 1/2 the can, shut down the engine and disconnect the battery for 5 minutes, then restart and complete a number of mixed driving cycles, town, freeway, stop and go etc., after a few days the problem will go away as the system will relearn to the clean intake

Here is the most common cause of surges and stalls and low idle, it is the idle speed control air-bypass valve and throttle valve (IAC for short), they get full of gunk over the miles and cause idle issues (stalls, low idle) like yours, Get a can of intake cleaner from any local parts store, not carb spray, intake cleaner, it is made by a company called CRC, remove the air intake hose to the engine, hold the idle high so the engine won't stall, then spray the can of cleaner into the intake while keeping the engine running, use at least 1/2 the can, shut down the engine and disconnect the battery for 5 minutes, then restart and complete a number of mixed driving cycles, town, freeway, stop and go etc., after a few days the problem will go away as the system will relearn to the clean intake.