Sometime, spark plug cables can hide problem in the boot,
I mean half broken wire in the boot when pulling it off from the spark plug.
We have to make really sure that the cables are very good by changing all of them.
Also if the coil was crack and changed, it has put some stress on the # 4 spark plug wire even if it look ok.
Changing that wire or all of them could solv the problem.
Saturday, November 21st, 2009 AT 4:15 PM