yeah car has hestitation at like partial throttle and also notice plugs are black which means its running rich had my computer reprogrammed would that cause this problem or could there be something else changed all filters, plug wires, was thinking about changing o2 maybe to see if that would help

 

The chip could be causing your problems. Did you have it tuned for your car or is it just one of those One size fits all chips? You might as well change the O2 and see if that helps, espicially if you say it is only at partial throttle. Has the car been starting/idling fine?

 

well i think the program is for my car because when i send the computer off he ask what i have done and what i plan on doing? otherwise the car starts fine the idle is a little fun some it will go up to like 1000 then drop down normal or little below normal

 

Probably just your O2 sensor then.