2000 Silverado Misfires

[Beebe]

My 2000 Silverado 1500 5.3L 4X4 z71 tripped a misfire code. A friend of mine has a scanner that can read all cylinders and it shows 3 different cylinders are misfiring at idle. Sorry I do not recall which ones. I have 130,000 miles on it, and replaced the plugs, and wires around 100,000 miles.

I have the coil per plug set up. No cap and rotor. What can I do?

Thanks,

Dave

[txab]

Any intake leaks?

[wawa]

swap the wires around after you figure out which cylinders are misfiring. if the miss moves change the wires. if no change move the coils or plugs. if no change after all that you may have valve issues or lifter roller issues. check the pan for lifter roller bearings

[mtm700]

I would also suspect intake gaskets if the misfire don't move to different cylinders when the plugs/wires are swapped. There is a TSB out for intake gaskets.

[scoota1969]

I have the same problem with my 2003 GMC sierra 1500hd quadsteer missfires mostly 1,3,5,7 have done everything plugs,wires,fuel filter,gas pressure test,compresion test,MAF sensor,canned the k&n filter,checked everywhere for vacume leaks,only thing left is plugged cats or cam sensor i guess all the scanner says is random misfire runs rough idles low misfires spark knocks its just a mess really HELP!!!!!