I moved my car onto my driveway to change the steering shaft out and out of nowhere my car has started idling rough and my plugs are black, I'm at a loss for what this could be because i have replaced my IAC and my Throttle Position Sensor, The car had bad valve cover gaskets when i got it and I've replaced them with new ones, This car has me at a loss for what the problem could be, I have a suspicion that its the valve cover gaskets again as i could have botched it up but I was wondering if someone with a fresh mind on this could help me figure it out.

 

you should measure your fuel pressure first most of the time the fuel regulator goes bad