engine problems HELP!

[cowbomb02]

ok i just got a engine swap done for another ka24de motor in my 91 240sx. it was from a 93. after getting it installed there was a slight problem. the first day when the mechanic had turned the engine on he told me it was runing smoothly. he told me there were a few minor adjustments to be done so i decided to pick it up the next day. when i showed up the next day he told me there was a problem so he showed me . whenever he would rev the motor up, it wouldnt go farther then about 2500rpms. judging by the large ( more then normal ) amounts of fumes coming out of the exhaust he said that there might be a problem with the fuel injectors. he then stated that there could be some other problems but he wasnt sure. another thing i noticed when test driving it, whenever the car was idling it seemed like it was about to stall. the mechanic also found a broken ring from the cat if that helps any, but he replaced that. need some help guys thanks.

[cowbomb02]

also before i had the engine swapped, i had a bent rod in my stock ka. i just decided to drive it to the shop since i had no cash to get the car towed. as i was driving it smoke started pouring out of the car. i heard from another post that the cat couldve been clogged up really bad causing my problem. hopefully this will help if any.

[quiksilvia]

if this bent rod made really abnormally hot exhaust gas, it would have melted the innards of the cat. the bad idle thing could be a vac line messed up or timing is off. o2 sensor might be contributing

[240SX=fun4me!]

in all honesty, if ya wouldnt have mentioned the rod, I would say have the mechanic clean and check the MAF. I did my own inspection of the air box when i first got my 240, and when I put it back together, the car idleed horribly and died when i punched the gas hard.

jus my input