Can barely drive when car is cold
 

Hello everyone,

I've seen a lot of people having problem with their rx8 when it is cold but I have a strange one I believe.

When I start my car the morning, it starts fine then when I start driving, under 20mph everything is fine but I go over a little bit and the car switches to 4th gear (it's an automatic) the rpm drops really low and the car starts shaking like crazy and the rpm needle jumps from 1000 to 2500 back and forth until i release the gas pedal.

It kinds of reminds me of manual starter on old cars when it was cold and you would turn it off as the car is still cold it would shake then stall.

It's like the automatic transmission swithes to 4th gear too early and the rpm is too low for the temperature of the engine.
Can this be fixed by an ECU upgrade?
It's an rx-8 from 2004.

Thanks a lot in advance.

How many miles are on the car and when was the last time the tranny was flushed and fluid replaced?

could be a transmission problem
check out the fluids first

Hum. Maybe the compression is going out. :( After you check the simple things might want to consider that.

The transmission switching to 4 gear to early has nothing to do with low compression. After the fluids have been checked or even replaced. The ECU ugrade will not help. The TCM controls the tranny.

So the car has 45000 miles, fluids are all good...

At what speed and rpm is the car runing in 4th gear when you having the problem?

Around 25-30 mph. If I try to go faster before the temperature's needle reaches the normal temp, and the car switches to 4th gear, it starts shaking so bad it feels like the engine is going to fall on the road.
To be exact this is not exactly right after it switches to 4th gear, it's when the overdrive (I think that's whats it called when you drive and if u keep a constant speed there's some kind of a 5th gear that lowers the rpm a bit), so when my overdrive goes off the rpm is so low for the temp of the car that it can't handle it.

does it make a clicking sound?

Nope just feels like it's about to stall but no specific sound