Upshift Delay on 93' 400E
 

Hello -
I just recently purchased a Mercedes '93 400E with 160,000 miles on it.. And the check engine light came on after about 20 miles. So I press the X11/X21 button on the car, and the LED light gave me 26 beeps, which corresponds to a "Delayed upshift" problem... So I reset the check engine light(hoping that it would come back if it was a serious).

So, what should I do?
Is it worth getting fixed? or necessary?
A friend told me that it could be the spark plug seal leaking..
Anything would help.
Thanks

Really? No responses?

My buddy said it could only be a leak in a piston or something with the crank shaft?
I personally have no idea about cars so I'm just shootin blanks.