I changed the spark plugs and a few days later it started to have a rough idle and studder a little bit,when it gets over 1500 rpms its fine.


I also put a Thrush glasspack in place of the old muffler.Would that affect anything?

any suggestions?

 

change out your coil pack, that was my issue

 

Check ur wires.

 

What plugs did you go with?

 

I put in Motorcraft Platinum ,but i did not change the wires.

 

Reason I'm askingm is cause I went to a "better" plug, and my truck ran like crap. Went back to the original plugs, and it was back to normal.

 

do this bro.... put your truck in a garage with the lights off. pop the hood, start the engine, and watch for a little blue arc under the hood anywhere near any of the ignition wires/hardware. if you see an arc near a wire, change out the wires, otherwise, if you see nothing, do the coil pack.

 

try sea foam...

 

Change your plug wires. They are easily damaged when you pull them off your old plugs.

 

This is true if the insulation is breaking down, but the core conductor can be broken, and you won't see an arc.