Spark Plug Wires - When to replace?

[2500HD4x4]

I am not having any problems with my truck, but as it has 308,000 miles and I'm doing general tune-up items, is there anyway to test my plug wires. Hook-up an ohm meter??

My general thoughts are, if it ain't broke, don't fix it. However, I like to maintain my vehicles well, so......

The only issue with my truck is a little cold start knock, but that goes away within a minute or two, which I've heard is normal.

Thanks in advance!

[MT-2500]

ohm/meter will only tell you if they are good or bad.
Not half good or bad.
If they have never been replaced now is a good time.
MT

[Crasen]

Plug wires are always a good part to change, they generally do not last all that long. An ohmmeter will ussually not tell you if a spark plug wire is bad. Spark plug wires are more likely to fail to to the insulators or boots failing, they can be chacked with an ignition scope, however since this is an expensive diagnostic machine not many people are likely to have one sitting in their garage. Heck many mechanics may not even know how to use one. Basically if in doubt always change them

[horse482]

If it is a pre-vortec then the wires are fairly inexpesive, you can get a good set for around $40. If it has been more than 60,000 miles since the last time they were changed then I would go a head and change them.

[sub006]

300,000 without a wire change? This truck is treating you right by running at all!

Forget $40. Put the best damn wires you can find on it. Should come with an iron clad lifetime warranty for the price - just save that receipt.

I suspect you haven't changed cap and rotor in too long. Change all three and you'll be amazed at the performance improvement.

[MT-2500]

Originally Posted by 2500HD4x4

I am not having any problems with my truck, but as it has 308,000 miles and I'm doing general tune-up items, is there anyway to test my plug wires. Hook-up an ohm meter??

My general thoughts are, if it ain't broke, don't fix it. However, I like to maintain my vehicles well, so......

The only issue with my truck is a little cold start knock, but that goes away within a minute or two, which I've heard is normal.

Thanks in advance!

I think the plug wires are due for a change as covered.
The only real good test on plug wires or primary ignition is a engine scope.
On the cold start knock as you say some of them it is normal.
But one thing to consider is the brand oil filter.
If you are not using the OEM type AC-delco oil filter.
Give one a try the next oil change.
I have found they control the engine running oil pressure and cold engine oil drain back better than a lot of other filters brands.
Also here is a link on oil filter testing that is interesting.
http://people.msoe.edu/~yoderw/oilfi...lterstudy.html
Good luck with your truck and may it make it to or beyond 500K
MT