ok i posted a post about my problem a couple of days ago! i have a 92 mustang gt.the car runs a lil rough and its missing alot.i gave it a full tune up,checked the timming!changed the wires,spark plugs,rotor cap ect,and the car is still running the same.but i knowist something wen i took one of the spark plugs out wen i was changing them. all of them were black exept for one.that dint looked as burnt as the other spark plugs.and it spelledalot likefuel.
Another thing that i found strange was,wen i pulled the wire to check the oil there was alot of suction there?i also open the oil cap and it was also suckin alot of air tru there? im starting to think that the problem is coming from the pistons. im not sure! has this ever happened to someone?or does somebody know what the problem can be? thanks alot!

 

sounds like that 1 cylinder is not firing

check why....wire not on all the way, etc.

 

it sound to me like a lean condition like not enough air, is your filter clogged, injectors failing, or is your distributor giving up, coils givin up theres alot that it can be...especially for them all to be black and only one not...did it back fire...

 

the car doent back fire.the motor just shakes alot and it sounds like is going to turn off wen i just let it sit there idealing.

 

i would be willing to be its a fuel problem hearing that, my car i know when my pump was going did that same thing shook alot and sputtered, pulled the plugs and they were black...do you have a fuel pressure guage hooked up to the car if so what does it say

 

That "suction" noise makes me think of vacuum leak.

 

yeah i would agree as well i totally for got about that