billerwin40513 wrote: ↑
Mon Apr 05, 2021 11:45 am
Just bought a 2017 QX80 three months ago and have the same issue...while starting off at low speeds it sputters like it wants to die but by the time I am at 45 or so, its fine. While cruising on hwy, no issue at all.
In stop and go traffic, the RPM bounces wildly between 1000 and 2000. Had code P2101 go off for throttle actuator motor. Replaced it and still the same thing happening. Got so bad after a week, took in again despite no codes showing. Replaced Mass Air Flow sensor and was told to use nothing but premium fuel.
After 3 weeks of that, still no change. Not sure if its a lemon or if all QX80s do this. Either way, its a pain as I am out more on repairs in 3 months that I am in car payments.
Did replacing transmission fluid and filter help as noted above?
Hopefully I can point you in the right direction.
Your issue is different than his, you have problems at low speed as his is under load. I have heard of others having, what they call, RPM surge. Not sure this is what yours is doing. But at lower RPMS, say 1500, and going at low speeds (25-35MPH), your RPMS start to surge, this is caused by your transmission shifting to far up (4 or 5), when you should be in a lower gear (2 or 3), to determine it isn't the transmission, down shift manually to see if the surging stops and the vehicle drives smoothly like it should while you manual shift. If yours cleans up after manually down shifting into a gear that you should be in, it's more than likely your fuel pump in the tank. Note sure how to explain why its the pump, but low pressure coming from your fuel pump will cause your transmission to shift way to early, causing a load on your engine that gives you that surge at low RPMs/speeds. You can do a search on Google, you will find a few people with early QX and even Armadas with 100K miles that discuss this surge issue. Again, I hope this helps and points someone in the right direction!