2000 323i acceleration problem

Just had the devil in the shop where I had the cam sensors replaced. I thought everything was fine until, in heavy traffic, I had to get on the gas hard to merge. The engine hesitated and did not respond well and the "Service Engine Soon" light came on. Immediately thereafter, I stopped at a stoplight to find the engine running very rough, shaking the entire car. I nursed her home. Having no time to even look at the problem that night, I started the car the next morning - no "Service Engine Soon" light and no trouble, that is, until the next time I had to accelerate rapidly. The problem is consistent; I restart the car and the engine runs normally with no warning light, but the next instance of heavy acceleration messes with the works again. Any ideas as to what might be going on here would be deeply appreciated.

Get your engine codes pulled. Then ask us.