89 toyota supra non-turbo having issues

[Richie]

I just wanna say nice site and i have a small problem ... I bought a 89 toyota supra non-turbo and it was running fine all winter but lately its been having issues...

first ...it starting put puting.... so I did a tune -up

second when i finished i noticed it started to let out black smoke when i started it in the mornings for like 30 seconds then it would go away...

third..now it constantly put puts and lets out black smoke everytime i stop and go but when its going it dont smoke but still putputs..... when i punch it it takes off hard and fast but when i go easy on it it putputs and smokes..... Im confused... I added lucas to the oil and to the gas for treatment and put octaine booster but it still putputs......

the tune-up was done not even 1 month ago and the oil is black and i put 10/40 .... so my question is what do you guys think is wrong with it?

could it be my oxygen sensor? clogged converter? dirty fule filter? i dont know and its a colector but im getting real pissed off with the car and im ready to junk it..... its a shame cause it runs real strong on the freeway so any suggestions would be appreciated...and i dont take it to a proffesional cause i dont have the money to .... and no check engine light on so im wondering what could it be....please respond i really need help tyvm ttysoon

by the way it has a 7m-ge motor