engine running rough
 

well i upgraded my fuel injectors to the 703 neon injectors and everything was working fine and then everything went south the check engine light came on i have fouled spark plugs
one code said something about bad 6th injector
it smells like exhaust/gas when running
and i have black smoke coming out my tailpipe when i accelerate hard
and the engine feels like its sputtering
since this all happened ive changed the bad spark plugs and i put my stock injectors back in the engine still sputters like it did with the neon injectors it still smells like exhaust/gas when running
but i dont have as much black smoke coming out my tailpipe when i accelerate hard

From the description and the code, the sixth injector is stuck open. Pull it out and test it

well i understand that but ive taken them all out and put my stock injectors back in

fuel pressure reg bad?

could have damaged the O2 sensor??

My 97 cherokee was running ruff for months. Replaced tps iac nothing worked. Then I replace both 02 sensors and BAM ran great. No rough runs.

thanks but which one i changed the upstream one when i bought the jeep
do yall think it could be that one again or should i change the downstream one