99 e320 limp mode - EGR?
 

Might buy a 1999 E320 with 160K.
Check engine light: P0400 (EGR malfunction).

Test drive:
Car starts, but has almost no power - can barely get to 10 mph. Rev's a bit while parked, but not much. Owner said started happening 4 days ago when it could only get to about 30 mph, so it is worsening. So I guess this is limp mode, no...?

Disconnected the air mass meter terminal - no change, so that probably isn't it.

Also noticed moderately leaking transmission fluid, wobbly serpentine idle tensioner pulley.

The car is in great shape body and interior-wise, and we like it, just hoping the problem isn't going to turn out to be extreme. Is there an easy way to disconnect EGR to confirm whether it is that and/or to make it possible to drive it the half hour to our house?

And any opinions? Does a bad EGR system cause such a severe power loss and/or limp mode? Felt like it had about 1 horse power, and felt like maybe it was being starved for air.

Thank you in advance.