starting prob when cold(poss common fault?)

having replaced the obvious on 1.8 petrol freelander,because it took ages to start when cold, but would run all day till next morning. I resorted to have ecu read for any faults . this showed fault on temp sensor telling ecu that the engine was hot when it wasnt, had fault cleared. drove it home and replaced the temp sensor(£10) on front/ right of head. has not started as good when cold. moral of story is do this first even if no lights illuminated on dash as it will save guess work.wierdly previously if i disconected battery for half hour and refitted it it would start better