This definitely sounds like a disconnected MAF, possibly the MAP sensor or the junction connector to the harness.. if you got a CEL you can pull the code and get a better idea what it is..

I can reproduce that exact symptom by disconnecting the MAF sensor on my car..

If the sensor was dropped or grunge got into it when it was out of the car, its possible it became damaged..

 

Thanks a lot guys. I am going to mention all that to the mechanic. Meanwhile he sent my car to our local mitsu dealer. They will look at it on Monday. I think he may have damaged the maf sensor and is acting like he didn't do anything as some of you have stated... Thanks guys, this is why I like this forum...

 

I know this might also sound stupid but the problem you are stating is exactly what happened to me when I Installed my intake. I literally had to drive out of boost for a week till I could get the car re-tuned.

 

sounds like a disconnected i/c pipe black smoke/ no boost...