Hey Scotty,
I have a 2005 Chevy Impala LS with 140,000 miles. I have this issue where randomly while accelerating between 65-70 mph, the RPM’s will pulse jumping up and down 300-400 RPM’s. It has been doing this for well over a year, but it doesn’t happen all the time. I was just wondering if you had any idea what it could be? A Google search shows this is an issue others have had with this car but I can’t find any posts where anyone has figured out a fix. Anyways, love your channel and just wanted to know if you’ve seen this before. It’s nothing major, just a mild annoyance.
Sounds like the transmission lock-up solenoid. Which locks the torque converter at higher speeds (for better gas mileage).
It almost feels like a soft gear shift when engaging at higher speeds (somewhere over 45 mph).
Your RPM's will drop a few hundred when it engages, and rise the same when it disengages.
Pretty common for it to pop on and off when accelerating or using cruise control on hills.
