Did you pull off the wires at the coil and check for any signs of corrosion?

Are these random misfires?

How old are the wires.

Even minor arcing isn't good.

Answered by Service Writer (expert)
9,955 answers provided

no cor. just a grease substance on coil end of wire misfires seem to be more random than a sure circumstance i was told at time of purchase (4 months ago)that plugs and wires were changed

Response from bob r 007
1 question asked

Any loss of coolant on this?

These are common for intake manifold problems that will cause misfires....Generally they don't tend to be moisture related, but could be consistent with the hot motor.

Are they decent wires or cheapies?

Pull a plug and check gap or condition at all?

Answered by Service Writer (expert)
9,955 answers provided

holds all coolant wires seem thinner than some that I've seen is this common for this type of car or a good indication of cheapness!! yes my next step was going to be to check plugs and wire ends at plugs boots etc

Response from bob r 007
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Usually there is a name brand on the wires..have seen cheap ones fail.

Good news on the coolant!

Answered by Service Writer (expert)
9,955 answers provided

what type intake manifold problems might exist on this engine to cause random misfire

Response from bob r 007
1 question asked

http://www.autoblog.com/2006/04/15/gm-to-handle-intake-manifold-gasket-problem-on-a-case-by-case-ba/

http://www.complaints.com/directory/2005/october/1/31.htm

A google search will give you more,

But in a nut shell, there is a coolant passage in the mainifold that gets eroded from heat and hydrolic pressure that corrodes an opening internally.

The plastic manifolds are a problem child, and have seen engines lock up because it can be that quick.

Happened to my Boss..twice LMAO!!!!!

(did I laugh out loud ?) :)

Answered by Service Writer (expert)
9,955 answers provided

wow sounds serious is there a test to verify such a problem

Response from bob r 007
1 question asked

Compression test.

Pull the manifold off and evaluate it.

Symptoms include:

Pull the plugs and look for coolant burning.
Loss of coolant.

PO300

Answered by Service Writer (expert)
9,955 answers provided

lets say that new plugs and new high quality wires are installed, compression is passable, coolant is full , and the same thing happens. what are some other alternatives

Response from bob r 007
1 question asked