Rough idle, lots of vibration, sluggish acceleration, shuddering at low speed

[19tahoe]

2014 Chevy Tahoe LT (rear wheel drive) with 170,000 miles,

Experiencing consistently rough idle, with lots of vibration, consistently sluggish acceleration, occasional shuddering at low speeds (under 15 mph). No codes, no check engine light.

https://www.amazon.com/Veepeak-Bluetooth-Diagnostic-Supports-DashCommand/dp/B011NSX27A

I have this ^ Veepeak OBD II scanner, but I am clueless when it comes to vehicles and I'm not sure what to make of the live data.

I put in new AC Delco plugs, wires, and coil packs, no improvement. Cleaned MAF sensor, cleaned throttle body, replaced air filter, no improvement. I tested the fuel pressure at the fuel rail and it seems to be well within spec, so I will assume the fuel pump is OK for now. I tried spraying carb cleaner around the hoses to hear if the engine revs up due to vacuum leak but it didn't seem to at all. There is no PCV valve on this thing from what I can tell and the PCV hoses & connections look fine.

I used "Gumout - All in One fuel system cleaner" when I filled up the tank from close to empty, and it did seem to idle smooth in the parking lot and ran decent on the drive home, (still a bit sluggish when accelerating), but began idling rough again the very next time I started & drove it.

The injectors have at least 130,000 miles on them, and may even be factory original (170,000 miles). So, they may be long overdue for replacement. Amazon has ACDelco GM OEM injectors for $55 each (nearly half the price of local parts place) on their ACDelco Amazon store (I assume that means these parts are genuine?) but before I spend $470 on 8 new injectors, I wanted how to rule out whatever else it could be (O2 sensors, catalytic converter, etc.?), and would love to know how exactly to test before I throw any more parts at this problem.

Any idea how to troubleshoot from here? Thank you for your time!




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I’m having this same exact issue, have you figured out what the problem was? I just got my Tahoe back from the dealer and I have a brand new transmission and motor mount. I also did a full tune up (Spark plugs , wires, and air filter.) I can’t seem to figure out why it it feels like it’s vibrating hard around 1,000-1,500 rpm around 10-15 mph.

 

[OR VietVet]

I’m having this same exact issue, have you figured out what the problem was? I just got my Tahoe back from the dealer and I have a brand new transmission and motor mount. I also did a full tune up (Spark plugs , wires, and air filter.) I can’t seem to figure out why it it feels like it’s vibrating hard around 1,000-1,500 rpm around 10-15 mph.

Welcome to the forum from Oregon.

You really should monitor this thread and ask a few questions but start your own thread and you will get more help/responses.

 

[Fless]

I’m having this same exact issue, have you figured out what the problem was? I just got my Tahoe back from the dealer and I have a brand new transmission and motor mount. I also did a full tune up (Spark plugs , wires, and air filter.) I can’t seem to figure out why it it feels like it’s vibrating hard around 1,000-1,500 rpm around 10-15 mph.

The OP hasn't been on here in two years. You might consider starting a new thread.

 

[j91z28d1]

I’m having this same exact issue, have you figured out what the problem was? I just got my Tahoe back from the dealer and I have a brand new transmission and motor mount. I also did a full tune up (Spark plugs , wires, and air filter.) I can’t seem to figure out why it it feels like it’s vibrating hard around 1,000-1,500 rpm around 10-15 mph.

if I had to guess I'd say the dealer messed up your driveshift. I'd take it back and have them test drive it.

 

[91RS]

I’m having this same exact issue, have you figured out what the problem was? I just got my Tahoe back from the dealer and I have a brand new transmission and motor mount. I also did a full tune up (Spark plugs , wires, and air filter.) I can’t seem to figure out why it it feels like it’s vibrating hard around 1,000-1,500 rpm around 10-15 mph.

One engine mount or both? If you only had one replaced, you are now feeling the engine vibration through the collapsed right one.