Question about GMC Envoy
The "Tachometer" is the gauge that indicates the engine RPM. It is not unusual for the idling RPM to drop slightly when the air conditioner comes on. The air conditioner represents a fairly large load on the engine so when it starts, the RPM will drop slightly. When driving, you'll probably not even notice that the air conditioning is a load on the engine unless you're accelerating uphill, pulling a trailer or passing another vehicle while the vehicle is fully loaded. At idle, the Envoy's computer should detect the falling RPM and make adjustments in fuel delivery to bring the RPM back up.
In any case, it shouldn't be cause for alarm, unless the air conditioner is stalling the engine. If this is the case, you are probably in need of service. The issue of low cooling from the air conditioner while idling in gear (as is the case when stopped in traffic, etc.) is correctable free of charge at the dealership on certain vehicles as a result of a recall. Your dealer can tell you if your vehicle is affected or if there is other recall work pending on your vehicle based on the VIN.
I hope this helps!
Posted on Nov 04, 2009
a 6ya Mechanic can help you resolve that issue over the phone in a minute or two.
Best thing about this new service is that you are never placed on hold and get to talk to real repair professionals here in the US.
click here to Talk to a Mechanic (only for users in the US for now) and get all the help you need.
Posted on Jan 02, 2017
Tips for a great answer:
Dec 08, 2013 | Cars & Trucks
Oct 09, 2010 | 1993 Nissan Pathfinder
May 18, 2010 | Cars & Trucks
Mar 05, 2010 | 2007 Lexus ES 350
Feb 27, 2010 | 1997 Buick Riviera
Aug 20, 2009 | 1996 Jeep Grand Cherokee
Jun 13, 2009 | 2005 Kia Rio
Feb 28, 2009 | 2002 Volvo V70
Jul 16, 2008 | 2000 Suzuki Vitara
320 people viewed this question
Usually answered in minutes!