GMC Acadia Forum banner

Engine hesitation at idle

9K views 7 replies 4 participants last post by  gurufly 
#1 ·
This morning on my way into work I was stopped at a light and suddenly heard and felt the engine sound like it wanted to die. The RPMs were at 600 and I could see the needle bounce very slightly and the car was bucking for about 2-3 seconds. I had the radio softly and when I turned it down, I even heard a stalling-like sound from the engine. My commute is very short (approx 5 miles) and it only happened this one time shortly after I started into the trip.

I've noticed this same thing a few times in the past, typically after washing the car. I go to start it up and there is an immediate(or within a minute) hesitation from the motor for a few seconds and then all is fine after that.

Does 600 seem too low for the RPMs at idle? Anyone have similar experiences and figure out how to resolve it? I had a modified import a few years back and I had similar issues, but they were more constant. There was a BISS screw with an o-ring near the throttle body that I could turn to adjust the RPM idle. Anything like that on the Acadia?
 
#2 ·
Happened to me yesterday and I was really surprised. Car is in for the 5/8 transmission flash right now and I have no idea if it will affect it or not but am curious.
 
#3 ·
600 rpm is the set idle speed for the Acadia, 700 rpm if the A/C compressor is on. I don't think there is any way to adjust the idle speed without reprogramming it into the ECM.

You might try disconnecting the battery for a minute or two to see if it is a glitch in the ECM that can reset itself.
 
#4 ·
I don't think the 5/8 flash will fix anything. I've had my Acadia in for both updated Flashes, and it is still there. Just had the 5/8 flash done about 2 weeks ago.

GeoHawk, thanks for confirming the idle RPM. If I disconnect the battery, I'll surely lose all my presets. Not a big deal, but do I also need the radio code(from the back of the radio) to unlock it?
 
#5 ·
imgntht said:
GeoHawk, thanks for confirming the idle RPM. If I disconnect the battery, I'll surely lose all my presets. Not a big deal, but do I also need the radio code(from the back of the radio) to unlock it?
You may lose your presets, but maybe not. I had a problem with a loose battery cable on my Silverado that would cause the radio to reset to XM Channel 1 and 12:00, but the presets would stay intact. As far as the security feature of the radio, THEFTLOCK works by reading the vehicle VIN number, I believe from the BCM (body control module). So as long as the radio is not removed and attempted to be installed in another vehicle, disconnecting the battery should not have any affect on it.

I know on our Odyssey we used to have the radio code stored someplace for whenever I would run the battery down from listening to the stereo without the car running. :tard: You shouldn't have this issue with the Acadia.
 
#6 ·
imgntht said:
GeoHawk, thanks for confirming the idle RPM. If I disconnect the battery, I'll surely lose all my presets. Not a big deal, but do I also need the radio code(from the back of the radio) to unlock it?
I disconnected the battery cables several times while replacing speakers and never lost my presets.
 
#7 ·
black72 said:
I disconnected the battery cables several times while replacing speakers and never lost my presets.
Thanks, good to know!
 
#8 ·
I used Top Tier gasoline (Turkey Hill) and it seemed to totally take care of this, FWIW. Same octane (87).
 
You have insufficient privileges to reply here.
Top