Engine misfiring

[03 SLT1500 4x4 4.7]

i bought this truck not long ago with 178,000 miles on it. it had problems at idle and stop and go traffic. rpms would jump slightly and it would sometimes kill itself, i think that might be the idle air control valve... but i recently changed the plugs. i put auto lites in it, not the champions that wore in it, the engine started to run rough at cruising speeds (45-55) but no problem at idle....a few hours later and now it has a misfire on what feels to be both sides of the engine... i hate the coil packs this engine has and have never had such a headache from changing plugs. dose anyone have any input anything please

 

[jbmobbs]

my step brothers did that last month and we upgraded the coilpacks and wires we used msd coils and accel wires and it fixed it

 

[HemiBabe]

Welcome to RF.

I would try replacing the wires as well, is it throwing a code?

 

[USMC1188]

X3 on wires and coils. Sounds like it might just be time for a real good tune up. Check for vacuum leaks and the like as well, clean the MAF sensor etc.

 

[Joshwaa]

Don't forget to change the coil pack boots also.