Low RPM idle and vibration 2011 Tahoe Z71

Hello all. First post after owning the above mentioned Tahoe for a month. First I will list all I have done to it:
AC Delco everything
-air and oil filter with oil change
-plugs
-wires
-coils
-MAF
-MAP
-O2 sensors
-cleaned injectors
-cleaned throttle body
-cleaned throttle body connector
-checked for intake leaks

At stoplights it idles at 500-550rpm. It doesn’t struggle to stay running and the idle is much improved after the tune up. Occasionally it drops a tiny bit below 500rpm. It’s a little rough still. Am I missing anything? Oh I’ve done a fuel trim reset, idle relearn, crank sensor relearn, oxygen sensor relearn. Any ideas? I figured it would/should idle around 600-650rpm.

RocketcCutlass said:

Hello all. First post after owning the above mentioned Tahoe for a month. First I will list all I have done to it:
AC Delco everything
-air and oil filter with oil change
-plugs
-wires
-coils
-MAF
-MAP
-O2 sensors
-cleaned injectors
-cleaned throttle body
-cleaned throttle body connector
-checked for intake leaks

At stoplights it idles at 500-550rpm. It doesn’t struggle to stay running and the idle is much improved after the tune up. Occasionally it drops a tiny bit below 500rpm. It’s a little rough still. Am I missing anything? Oh I’ve done a fuel trim reset, idle relearn, crank sensor relearn, oxygen sensor relearn. Any ideas? I figured it would/should idle around 600-650rpm.

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Lots of people here have reported similar symptoms with their only resolution being to bump the idle speed up a bit to 600-650, as you say. You can do this with hptuners or you can pay a tuner to do it for you. My '07 XL Denali idles at around 550 and it's smooth, so go figure.

Unfortunately, that's pretty normal for a stock motor and they sometimes even stall if you come off the gas too quickly. The motors idle much better like where Dave says.

Mine idled low but had no issues with it. BlackBear when tuning my truck turned it up to 600 at my request.

Well crap lol. I guess I’ll be getting a tuner then. I was wondering if it was an AFM issue but it had a range unit plugged into the OBD port when I bought it. I like to do this myself so what’s a good tuner to get or does it even matter?

RocketcCutlass said:

Well crap lol. I guess I’ll be getting a tuner then. I was wondering if it was an AFM issue but it had a range unit plugged into the OBD port when I bought it. I like to do this myself so what’s a good tuner to get or does it even matter?

Click to expand...

You really can't go wrong with Blackbear. Justin has probably forgotten more about tuning these trucks than the average tuner will ever know. It is pricey, though.

The process is that you buy an Autocal device from them which comes with a credit for a custom tune. You connect the Autocal to your truck and drive for about 20 minutes on the highway and around town with a couple of full throttle pulls to the speed limit. Plug the device into the USB port on a PC and email the files it generates (one for engine, one for transmission) to Blackbear along with any special requests you may have, such as to adjust the idle speed. A week or two later, they will send you two custom tune files back that have been developed specifically for the unique parameters of your vehicle. Justin will also tell you if he sees anything wrong with your truck from the data.

I've had them tune both of mine and I'm very happy with the results. It really wakes up the truck and the transmission shifts are better with less clutch slip meaning that the transmission should last longer.

I fought the same battle and settled at raising the RPM and running premium fuel. My idle still stumbles sometimes but it’s pretty darn smooth now

^^^x2^^^ Blackbear tune. ~$650 TOTALLY worth the cost.

RocketcCutlass said:

Well crap lol. I guess I’ll be getting a tuner then. I was wondering if it was an AFM issue but it had a range unit plugged into the OBD port when I bought it. I like to do this myself so what’s a good tuner to get or does it even matter?

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We would be happy to help with a tune. Give us a call 877-809-4070 or email us [email protected]