This has probably been asked before, so many apologies. So around 50-60 my mini jumps to 4-5 grand. It will come back down slowly, but it surges again around 65. Its an 09 auto, no mods. Any suggestions? Please don't say bad tranny, its been a bad week haha. Cheers

 

Does the car speed up with those surges? If you are accelerating during that time, does the acceleration increase or decrease?

Do you hear the engine spin up in RPM when the gauge shows it going up?

Could be a tach problem, could be the torque converter, could be a bad trans... Could be a lot of things.

 

yes acceleration will increase, slowly. I just had the belt changed, so i didn't know if that might have messed up some type of computer issue. This is my first mini, love this lil thing

 

I am no expert by any means and have a 6-speed mini but I've had a bad transmission in another vehicle and the rpms and engine would surge WITHOUT acceleration, so if it's accelerating proportionally with the rpms, then I'd guess it at least wasn't slipping, but could be something else related to the transmission like the suggested torque converter. Can you feel it down-shifting (before rpms surge) and up-shifting (before rpms come down)?

If it isn't accelerating proportionally with rpms, then I'd answer Slave's question as to whether the engine is revving proportionally with the tach. If not, then it's probably related to the tach.

 

If this is happening while you are on cruise control, I would think it is trans or torque convertor related.