ok heres the dish. i had a 91 2door teg. i pulled the motor/trans/ecu/axels....ect. out of it cuz the car was junk. i sweat the beans out of 4door teggies. ok so anyhoo this kid had one with the oppropiate obd0 ls in it (i bought it)......but it had that hesitation between those two rpms...no matter what gear ( gettin on it or normal drivin conditoins). so i pulled the motor out of thre 4door(high mileage,knock during start up that only gets worse, ect) and put my 2door ls in it. ok so heres the thing. my motor from the 2door does the same thing in his 4door.

the only things that i reused....
-his ''brand new'' dist.\
-chassie (meaning all the relays, actuators, ect.)
-fuel filter/pump.

all the things im thinkin it could be.....
-vaccum
-his old fuel pump/filter ( but not really cuz why would it malf. only between those rpms)
-tune up (wires, ''gapped plugs''[for all u lazy ******/kids who cant do a simple tune up], dist, fuel filter, ect.


i dunno: theres a lot of stuff to be looked over i guess....but the only thing that gets to me is trying to figure out what it is that i reused that makes my motor do the same shyt. today is sunday....and itll be back in the shop tomorow. so any hint or things that i havent thought about up untill this point befor i get crakin on it would help.

grassyass

 

distributor might be new but defective fuel pump .... eh... possibly

 

First thing I'd do, and the easiest, really, is change the plugs to NGK factory specs and try a different set wires, preferably OEM. Every time we had a car with hesitation like yours, that's the first thing we checked. 9 out of 10 times, that fixed the problem. Hopefully it will work for you too.