irratic engine performance

[the wood servan]

I have sprinter 311cdi I replaced the alternator recently, not the dealer (at 707.88 euros after a deduction of 118.00 euros!! for my old one) I disconnected the batterie before doing this. Now the engine sometimes runs OK but most times it is restricted to 3000 revs. If I stop anywhere it will refuse to start unless I leave it for about an hour. No it is not overheating, at least the gauge says not. Any help please

 

[mersum1es]

You may have several issues; hot starting problem is usually crank shaft position sensor, limp mode can be anything starting from faulty/dirty MAF to boost pressure problems...