Engine replacment help pls

[Graham]

i have just had a 2nd hand engine putin my car but not really sure wheather to reset the ECU after the garage have finished with it as i dont know how they have driven it after fitting the engine will it matter and also how many miles will i have poor MPH for i do a lot of miles and really could do with good MPH asap please advise ....... :¬

Graham

 

[Ozric-Al]

Wont make a lot of difference but leave the battery disconnected for an hour or more. Switch on and leave running for 5 minutes then go for a drive as normal.

Expect lower than ave MPG for the first 300 miles.