I have a 99 GMC Suburban K1500 4WD 350V8. I have put premium rotor caps and plug wires on this vehicle and after a month of driving the car on accellerating to freeway speed starts jumping around as if the front end is totally misaligned or it has a bent rim. On letting up on the gas this corrects it’s self to a certain degree. It turns out the rotor caps keep shorting out internally. A test of the cap will show the cap has direct shorts between say plug wire connection 1 and 2, maybe some others. I keep going through caps which start out new and not shorted. What could be the problem that is causing this to happen?
Any help from anyone would be helpful.
Thank you,
My first suggestion is to return to stock ignition system including OEM wires, plugs and cap. See what happens.
Those designer ignition parts seems to cause more problems than the fix.
How many miles on the truck? A problem, either mechanical (low compression, head gasket, intake leak, etc) or a fault with the plugs and wires can kill the cap and rotor.
This is not one of those “leave plugs in for infinity” is it?
Check the 5 and 7 wires to make sure they are connected to the right cylinders.
There should be a vent screen in the distributer that is supposed to vent moisture out, this could be clogged causing moisture to foul out the cap. Is there rusty powder inside the distributer?