accord loss of power

I had a friend of mine change my belts on my 94 accord (5 spd) (180k miles),
and now I have a sudden loss of power, specially in the low rev's, less than
3k. It's like it has no torque whatsoever. He has no clue what the cause
is and he swears he did everything right (sure). Any ideas?

To give you an impression of what's it's like, in first gear, starting from
0mph, it'll take about 5 seconds to get to 3k revs, in a normal start.

He's changed the belts before on other accords and the other ones are fine,
the only difference between those and mine is that the others are
automatics.

I was reading another thread about oxygen sensors, could that be it?

thanks

 

The new timing belt is off by one tooth. He's going to have to re-do it.

 

thanks for your answer......now another question:

he fixed it and I got back about 90% of the power back. In low revs (less
than 2k) it's still a little slow, but not by much. Should I expect this
after changing the belts? Any other ideas? thanks for your response.