I just got a 84 z28 with rebiult 305 ho in it,well it run good then I seen the carb (ele Q-jet) was leaking so I got a used 1 from the yard for it ,plus new plugs,wires,well heres the problem I put used carb,wires,plugs on & it had a bad miss & black smoke bad,so I put the old carb back on well it was still missing ,black smoke bad,I drove it home like that about 36 miles and it had power,just smoked real bad and messed real bad when going slow and not so bad when going faster,tryed truning the timeing dont help,reset the computer didn't help,it sems to me like it's getting way to much gas,I hope you's guys can help with this problem,I cant figer it out !!!!!!!!!

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maxz1

The carb. your running im sorry to say is junk. The only way i ever fixed that problem was to buy a new one or send it out for a complete rebuild. The elec. run your fuel curve and th esoleniod on those carbs always go out, then the car runs like junk and smokes. My advise is to go buy a new one, call the carb shop and see what they can do for you.

Sounds like your computer is not going into the closed loop mode as needed. You're running in the "limp home" mode which is pretty sloppy. Need to find out why the computer is not working right. Find a friend or a mechanic with a scanner and chech out the system. These cars run pretty good when right and get 22 - 24 mpg easy. Worth spending a few bucks on to get it right. tom

I'm glad you said that, I was fixing to can the comupter and put reg carb on it,the red light is on I didn't check the codes because I don't here a scanner,it hard to find the problem with the computer,it may well be what you said, is black smoke gas or oil ???? THANKS FOR YOUR HELP!!!!!

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maxz1