My 2003 Chevy Silverado is running rough?

My 2003 chevy is acting like its out of time. It running at a rough idle. What could be wrong?

• its a 2003 silverado with a 5.3 liter and 70,000 miles. The code scanner says multiple misfires with no specifc cylinder. It idles rough and acts like its out of time. It has no power to take off. A friend suggested i change the knock senser. Does this sound right?

• Answer:

  There is a number of issues that can cause the problem with your silverado.The knock sensor can not cause this type of problem.To find this type of problem a dealers scanner can see whats going on while the engine is misfiring.Most common would be coil pack shorting out or EGR valve sticking causing internal vacuum leak droping engine power.Best of luck.