I changed my spark plugs yesterday and found the rear trailing plug had alot of corrosion on the end that connects to the spark plug wire. the wire cap was very rusty as well. when i took it out it was completley black, totaly different from all the other plugs. none of them had rust, nor did their wires. the end of the wire that connects to the coil was rust free on all four wires. i havent had any power loss, but maybe is always been like that so i just dont know. is there a way to test of that wire is gettig power to the plug? is so how do i know its enough? i will post pics

 

most people here replace plugs, wires and coils together. pics would help. maby that wire wasnt fully seated on the plug

 

Said Pics

 

that was my first thought, but it was on pretty well, i didbt notice it being particualtty easy to pull off, but i wasnt really looking for it. i noticed how rusty it was when i was about to take it out

 

how old are your coils and wires? i would change them too

 

i bought my car new in 07 and havent changed them yet

 

This will help you test your coils and sparkplugs wires, DIY: Testing your... Coils and Sparkplug wires

 

Just wanted to let you know that I had the same issue with my plugs and coils. I think the rain we had in the SF Bay Area last year was the cause of the problem as I had driven through a section of road that was pretty well flooded and it may have splashed into the engine compartment. Both the lower plugs were corroded and the lower wire connectors also showed rust as well. I changed all of the plugs and wires and I plan on seeing if they have the same problem this year.