I have a 2000 Silverado 4.3 automatic 4x4.I have plenty of power for six cylinder[:'(], but sitting at a stop light it idles rough and seems to have a miss fire.The truck idles at about 650.If I bring the idle up to 800 it is smooth and the miss goes away. I have replaced,distributor cap+rotor,wires,plugs,fuel filter,fuel pump,cleaned the throttle body,installed a K&N air filter, checked for vacuum leaks, I now have no money and still have a rough idle. Can anyone help me????????

Oh yeah I replaced the fuel filter also. Any Ideas would be greately appreciated!!!!!

 

This may sound crazy but I had a similar problem and it was due to the Oxygen sensor. ODB II did not pick it up, just lots of years of working with these things and a really lucky guess.

I think all of them are made by Bo$ch($ is intentional) and are not made to last over about 40,000 miles(get a new set of tires--get new O sensor).

32$ and 20 mins worth of work and my problem went away.

You may have two... the manual showed vehics with 2 and 1...Yes on both the 6 and 8 cyls. Go figure.

If you replace it yourself make sure and put a teflon tape or approved sealer/antiseize to stop any thread leaks and make it easier to pull the next time. Many of the new sensors come with antiseize already on the threads. I'm strange and admit it and I actually put the tape on then some antiseize just to make sure it seals and I can get it out without a fight the next time(neither are suppose to hurt your emissions).

Hope it helps

 

You've probably fixed the problem by now, but for the sake of others.....

I agree that the problemMAY be an oxygen sensor, but you CAN test them before simply replacing them. Have a look here for more info Testing Oxygen Sensors