2000 Ford Explorer 4.0 v6 sohc. New spark plugs, cleaned the injectors, new upper and lower intake manifold gaskets. Ran fine before work was done. Now it shakes bad when it runs. Will not idle, and does not seem to fire on all cylinders

If you did the repair, go over your work and see if anything is unplugged. See if there are any vacuum leaks-Scotty has a YouTube video on doing this with a cigar, also check the PCM for any codes. If it has spark plug wires, be sure you didn't cross any of them to the wrong cylinders.