these days, when I run on the street and stepped on brake, RPM goes down to 1000 and up to 2000 unstably. is it time to fix timing chain?..
anybody knows what the problem is? transmission problem?

 

help me!!

 

ummmmmm

what year car ... what tranny .... S or Justa

I've no idea what your problem is from your post

 

it's 07 mini cooper justa... as I described, when I stepped on the brake and almost stopped, RPM goes goes down and up unstably...you know what I'm talking about?

 

no I do not know what you are talking about... but I'm trying to figure it out ...

stick or auto ?????

BIG difference . . . .

 

automatic.

 

Sounds like only a rough downshift when the RPMs are low enough to switch gears.
That has NOTHING to do with the timing chain.
Have you transmission fluid checked, and possibly changed as old fluid loses it hydraulic detergent properties and can induce hard shifts.

- Erik

 

I haven't checked transmission fluid yet but when you see attached, it says "replace transmission fluid at 100k. I just hit 63k..

 

Just because documentation says it could last 100K miles, doesn't mean it has or hasn't.
Personally, if the transmission was shifting as hard as you refer it to be, I'd be checking that immediately, making sure fluid level is up to par.
And if was up to par, and the tranny is still acting up, I'd check condition of fluid and most likely replace it.
No fluid that I've come in contact with in my days of being a lube tech can last the heat cycles and stress of 100K+ miles.

- Erik

 

I had the same problem and as mentioned here https://www.northamericanmotoring.co...ive-fixed.html
I reseated the MAF connector and tightened some hoses, the problem went away for me.

 

what's the maf connector?...