Hi folks ..
i have my 1995 cherokee xj ,, i i did a little modification to the car .. added a 2.5 inche long headers , and i swapped the intake manifold to + 2000 with an LS throttle ,, after i did all that i noticed when i hit the gas heavey acceleration the car feel like misfiring a bit but keeps moving , i berly feel it .. when it was all stock i havent had any problem with it , i cant figure out what the problem is .. anyone have an idea please help
thank you

Anyway , since no one respond ,
i swapped the intake manifold to a regular tb size
and solved the problem , so i think i had to replace the fuel pump to a better pressure to avoid misfire with bigger tb ,,

It was a 4 inches tb for LS1 , my friend have it in his car and have no issue , but i belive he replaced the fuel pump at early stage .. when i installed it on my car i noticed no huge differnce and face a misfire maybe the engine cant handle much of air flow , or 4inches tb is too big for a 4.0 engine