91 240sx press gas and rpms run low and engine makes popping? sounds...

[c0ldh3at]

bad problem need help!!!..my 240sx turns on great ...had a fuel pump problem and changed it...ran great..new alt. cap n rotor and spark plug wires ,fuel filter...when i was driving home the speed was dropping fast...was making a put put popping sound on the left side of engine..dont know if its coming from the exhaust manifold or not and saw a lil smoke come from it when i opened hood. today i cleaned the maf sensor and alt cap ...drove it around the block..wen in gear it'll shake alot and make da popping sounds and rpms slowly climb up..i have NO idea whats wrong i need help...if anyone knows wats wrong im me on [email protected] ..thanks

[dkdeleon68]

check your vacuum lines and intake for leaks

[c0ldh3at]

no leaks from wat i can see/hear but wen i move around the wire dat connects to my alt. the rpms go up den down back to normal which is in my car 7/900...still hear the popping sounds but havent had time to drive it on my block since i was doing it around traffic time...sigh...wat else could it be..oh yea i dont think i said this but wen i drove it last time in first gear the rpms will go all the down den climb up slowly but the car shakes hard n does the popping sounds

[MaximA32]

Are all of your plug wires in the correct spots?

[c0ldh3at]

i think so ...this is my eighth day driving my car...but if they aren't in what order should they be plugged?