Really low idle during stop and go traffic

[onecrazyfoo4u]

I've noticed recently that my 05 1500 with the 5.3l is almost dying on me during stop and go traffic.  It doesn't happen when coming to a regular stoplight or stop sign.  But when stuck in traffic or constantly stop and go, the idle will dip really low and the lights will dim like it's about to die; but it only happens when I let off the gas and haven't hit the brakes yet.  Hitting the brakes seems to bump it back up to 600 rpm.  The engine hasn't cutoff yet though.  My idle is usually about 550-600 rpm.  But when that happens it goes down to about 300 rpm or so, and then bounces back up to 600 rpm when I hit my brakes or come to a stop. 

 

Is there a way to manually adjust the idle?  Or would this be some type of sensor going bad most likely?  Thanks for the help!

[sefiroxx]

I've noticed recently that my 05 1500 with the 5.3l is almost dying on me during stop and go traffic.  It doesn't happen when coming to a regular stoplight or stop sign.  But when stuck in traffic or constantly stop and go, the idle will dip really low and the lights will dim like it's about to die; but it only happens when I let off the gas and haven't hit the brakes yet.  Hitting the brakes seems to bump it back up to 600 rpm.  The engine hasn't cutoff yet though.  My idle is usually about 550-600 rpm.  But when that happens it goes down to about 300 rpm or so, and then bounces back up to 600 rpm when I hit my brakes or come to a stop. 
 
Is there a way to manually adjust the idle?  Or would this be some type of sensor going bad most likely?  Thanks for the help!

Idle is controlled by the computer through the throttle position sensor which on these drive by wire engines, includes actuator for the throttle butterfly. Clean the butterfly/throttle body to make sure it's not sticking. You may have to replace the tps.

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[carnau]

You probably have excessive carbon buildup on the throttle body. Called throttle body coking. Get you a good small wire brush and some throttle body cleaner. Here is a video I made for cleaning a throttle body on a Trailblazer. It is basically the same concept just a different engine. If after you get done cleaning the throttle body if it idles high just take the battery cables loose (Both of them) and hold them together for 30 seconds. Then reinstall. Called a logic lock reset. Will reset the idle. Hope this helps.

Throttle Body Cleaner - http://amzn.to/2irzVJl

Wire Brushes - http://amzn.to/2xQRb1l

 

[onecrazyfoo4u]

Sweet, lets hope its something that simple!  I guess I haven't cleaned it since I bought it 2 yrs ago.  I'll give it a shot and hope for the best.  Also have a new air filter sitting in the garage ready for her. 

[Arth]

6 hours ago, onecrazyfoo4u said:

Sweet, lets hope its something that simple!  I guess I haven't cleaned it since I bought it 2 yrs ago.  I'll give it a shot and hope for the best.  Also have a new air filter sitting in the garage ready for her. 

 

Also gets my vote for the throttle body. Had this issue on a 2003 suburban. Cleaned the throttle body and there was some update for the ECU at the time and problem solved. Didn't have anymore issues with low idle after that.

 

Every spring I check and clean my throttle body now.