fuel mixture problem?

I have just got a custom cat-back system and now the check engine light is on. and I also notice black stuff being shot out of the exhaust becase i can see it on the ground. and it seem to have more gasoline smell from the exhaust

When I let go of the gas pedal and still in gear and moving, i can sometimes hear faint poping noise from exhaust.

also when i tap the gas pedal quickly the engine sounds like its gonna stall.

I belive the mixture is too rich, My question is How do i adjust the fuel air mixture on the PGM-FI system? Or is it some other problem?

oh one more thing, now that i got an intake and the cat-back exhaust for my prelude, no matter how i adjust it, the Idle wont stay the same.

Its a 1991 Prelude with a B21A1 engine.

[ebpda9]

that's weird. did u check the codes for the car ? i guess your car is a pre-odb so read this http://www.hondata.com/techecucodes.html i doubt there is a A/F mixture problem. it might be your timing that's messed up, or one of the oxigen sensors( that's their job to regulate the AF mixture in your exhaust gases)

thanks i am gonna go check it out

thanks I found out whats wrong with it, I put my intake too far into the rubber boot and it make the tube not alined to the throttle body and created some pressurized pockets at the boot and makes my idle crazy.