sold my 2003 cobra and bought a 2004 e55 with 48,000 miles 2 weeks ago. Wow I love this car. Please let me know if you have any ideas about these 2 problems I am having with my car could be. When i floor the car and let it shift by itself and tranny is in sport mode then let of the gas it stays in the lower gear reving at like 4500 rpms and does not upshift for 20-30 seconds. The car does not do this all the time as sometimes it will upshft right after I let off the gas. The other problem is usually when the car is cold and sometimes when warmed up it will stumble. This will happen under normal acceleration from a stop and the rpms are at 2-3k. This problem is very intermitent. One time this happened under hard acceleration right when the car shifted into 2nd gear. Thanks for your help.

 

honestly, it sounds like you may just need to get used to some of the quirks of these cars. the delayed upshift is normal. upon hard acceleration and sudden let off your trans will hold the gear for a bit just in case you need to get on it again.

for the second problem, it could just be s/c clutch engagement. to test it, put the car in 1st and accelerate very gently from a stop taking the rpms up slowly. if the stumble happens consistantly at 3500rpms it's your s/c and is normal. try that and report back...

 

I would check to make sure that you are not moving the car to MANUAL MODE by pulling the shifter to the left.

Your gear selection indicator on your dash should show C or S, and not a number.

 

+1

 

Reset the ECU. It fixed majority of my problems first couple of days home from the dealership. Let the ECU learn your way of driving then trouble shoot.

 

how do I reset the ecu?

 

Do a search for sneaky ecu reset.