Sluggish accelerating at 30-50mph

[Richard Blakely]

my 2012 Tahoe with 6 speed transmission is very sluggish when accelerating around corner especially. Changed max air flow sensor but no help. Runs fine cruising. Should I suspect fuel injectors or spark plugs next?

 

[kbuskill]

Depends...

More info would be helpful, such as mileage and maintenance history.

 

[91RS]

Did you just buy it or have you owned it for a while and this just started? It sounds normal but hard to be certain without actually seeing what it’s doing.

 

[Richard Blakely]

Did you just buy it or have you owned it for a while and this just started? It sounds normal but hard to be certain without actually seeing what it’s doing.

I purchased it about 3 months ago on a trade in. It had 120k miles and was doing this since day 1. Was blaming it on not being used to the 6 speed transmission, but feel that it may be a tune up necessary, although runs great when cruising. I only see the problem when trying to accelerate or rounding a corner. Also, AC when off sometimes will act normally, when on, will be sluggish. AC is functional, no problems.

 

[BG1988]

I purchased it about 3 months ago on a trade in. It had 120k miles and was doing this since day 1. Was blaming it on not being used to the 6 speed transmission, but feel that it may be a tune up necessary, although runs great when cruising. I only see the problem when trying to accelerate or rounding a corner. Also, AC when off sometimes will act normally, when on, will be sluggish. AC is functional, no problems.

see if it does it in tow mode

 

[ftwflh]

Mine was like that until I put on a Range AFM delete.

 

[Rob Haag]

I would put a scan tool on it and check fuel trims, o2 sensor data, throttle position sensor, all the basics, and go from there. It could be a number of things from catalytic converter, knock sensors, injectors, coils.. So many things. Even a $10 Bluetooth (or wifi for iphone) scan tool from Amazon would give you so much more to go on. You say you replaced the mass air flow sensor already but less than OEM quality can cause issues as well. Check what the new MAF is reporting too, you can't trust new parts just because they're new these days. Also be sure the throttle body is clean, but that will typically cause idle issues.

 

[91RS]

I purchased it about 3 months ago on a trade in. It had 120k miles and was doing this since day 1. Was blaming it on not being used to the 6 speed transmission, but feel that it may be a tune up necessary, although runs great when cruising. I only see the problem when trying to accelerate or rounding a corner. Also, AC when off sometimes will act normally, when on, will be sluggish. AC is functional, no problems.

This really sounds normal. The 5.3L isn't quite adequate for the weight of these trucks if you're looking for best drivability over fuel economy. I would definitely change the spark plugs and wires since they would be overdue if they've never been changed but don't just go throwing parts at it that you probably don't even need. My recommendation would be looking for a good local tuner and have the truck street tuned and that will help drivability quite a bit. Don't use a hand held tuner like a Diablosport or something, those are a waste of money. Your other option would be to take it to a dealer and let them look at it and they can tell you very easily if it's normal or not and that would likely be cheaper than loading the parts cannon.

 

[BG1988]

my 2012 Tahoe with 6 speed transmission is very sluggish when accelerating around corner especially. Changed max air flow sensor but no help. Runs fine cruising. Should I suspect fuel injectors or spark plugs next?

Transmission issue sorry..

I had a loaner impala 3.9 it was real sluggish in the 1 and 2nd gears you could pretty much floor it and it was still sluggish it was like driving a daewoo 3 banger and trying to race in it. (did not slip but something was off) the 0-60 was about 16 seconds lol
once in 4th,5th and 6th gear were fine..

I had a 5.3L Tahoe XFE with 6 speed ( title issue and return)
I did not feel this sluggishness you talk about.. 110k miles


on my hybrid i did feel it occasionally" sluggishness"(not talking about autostop lag) but everything was normal once I cleaned the battery terminals and resit them correctly and tight (that actually fixed all of my electrical problems including autosop/start lag from the Aux transmission pump)



it could also be a traction control issue that is something i would investigate
that could slow down the engine/transmission as well




I would start off with the battery connections and check them make sure they are nice and tight and clean terminals

If you watch scotty kilmer he says to check the cheapest and simple things first then work your way to the expensive items..


That is why I checked my 12V battery first before buying a replacement Aux pump that would have cost me over 600$ to replace for nothing

 

[Richard Blakely]

Thanks for all the comments. Greatly appreciated. After testing with trailer tow on, I found no sluggishness, although as expected, shift points were different. What’s interesting also during sluggishness, the tach doesn’t show any “blips”, making me think transmission