Z71crawford

Like the title say after i changed the spark plug and wires in my 08 i drove it and at idle if it sits long enough it will start pulsing every few seconds. The truck shakes a little and the RPMs drop a bit then go back to normal. I used Ac delco iridium spark plugs, with MSD 8.5mm wires for a 99-07 truck. Could the wires be the problem although i wouldn't think it would be? I know all spark plugs were locked down just right. What do yall think could be up? Is the computer learning the new thicker wires? Idk but in advance thanks!

nonnieselman

iTrader: (10)

i had a bunch of problems with MSD wires.. i got the cheapest ones the parts house had and no more problems..

i even got MSD to replace 4 of them and still no worky..
put your stock ones back on and see what happens.

shorty's garage

iTrader: (4)

I think anything from msd is junk. I make my own wires.

AUTOT3K

iTrader: (3)

Did you use diaelectric grease?
That's an insulator not a good conductor

Z71crawford

Yeah I think I may send these back! No I didn't use the grease. Probay go back to go old ac Delco

Chevy_King1500

iTrader: (7)

8.5mm msd wire worked great on my truck. you need to make sure they are 100% on the plug end.. they can be a little tricky

i would put the stock ones back on. if the problem still persist you may have cracked a plug..

Atomic

iTrader: (42)

Crack the porclein on a plug?

iamkeniff

iTrader: (16)

Shi i run TR-55 (5.3) an TR-6 (6.2) bosch wires. Cheap plug and wire change with no issues

Z71crawford

Trucks getting the 4.56s installed right is so ill do investagation when it get back.

LS1FREEK

iTrader: (1)

Ive had 3 sets of MSDs and never had a problem. If I had to guess, you may have cracked a plug.