2002 Mustang GT coolant leak miss fire

[FastLane]

I had a miss fire yesterday on the #1 cylinder. I scanned it and it was confirmed. I pulled the COP and spark plug. I put a new COP on and it ran fine. This morning it started miss firing again. I noticed my coolant level is low. I letting the engine cool off then I'll pull the spark plug again. I'll check the compression on the cylinder.

My question is what are the chances coolant is leaking into the #1 cylinder because of a blown intake gasket or cracked intake? Not the end of the world if I have to buy a new intake but I'm worried a head gasket blew out. I've never heard of 4.6 head gaskets ever being a problem. I know the intakes have huge issues.

There was no coolant in the spark plug hole but the spark plug looked rusty. Its only 4 years old. NGK Iridium.

 

[mk378]

What did the "business end" of the spark plug look like? When you have coolant going through a cylinder the plug will often look super clean and white compared to the others.

 

[FastLane]

 

[Silverado12]

Does the manifold have the metal crossover in the front?

 

[FastLane]

Yes it does. They leak too.

 

[JustinH]

Put a Bullitt intake manifold on it, and replace all the plugs. I have seen a bunch of those plastic manifolds leak and crack.

 

[FastLane]