2002 Hyundai Sonata Mis-fire on cyl 3 and 3 other error codes.

OK, I have a 2002 Hyundai Sonata V6. It has 214K miles and so far has had very few problems, mechanically. Afew weeks ago, I passed a car from stand still, after the sudden acceleration the engine started to miss. I replaced the plugs with no change. Took it to Auto Zone, an put it on the computer and found that a sensor on the intake manifold was faulty. As it fell apart in my hands we knew it was bad and replaced it. Still no improvement. Put it on the computer again and it comes up with Mis-fire on Cyl 3, and then P1505, and 1507 as error codes. As the car runs rough the miss fire is obvious. Where do I start to fix this.