B18 Vtec Engine Lagging?

I have a b18 vtec engine, and the other day i went to get it from the mechanic but the battery was dead. So he boosted it and all was good, but then basically right after getting off the lot i revved it up and drove pretty fast. But then when i slowed down the car started to lurch (i was in 4th) as if it was going to stall. So i try to accelerate and it happened again taking off in 1st. This only lasted about 30 seconds until it was back to normal. So, was it just because i drove fast right after getting a boost or was it because the engine wasnt "warm" or something. Any ideas would be great thanks.