Actually it wasn't doing this half as bad till i did the oil change (to 15-50W) from whatever was in before. When you say go up a grade what way do you mean?
I think the idle speed is a bit low. As i said it's erratic in that when i pull up it either goes what i would think 'normal' or real slow and often quits.
This engine went in less than 1k ago, was supplied by a place near glasgow and cost £330 so hopefully the engines not about to go. Like i say it feels good and strong. The invoice i got with the van said 'second hand'. Not much use there then... thinmk maybe i'll phone the garage who did it and ask them about it or take it in. Maybe they'll remember something about it.
