Ford Repair: 2001 Ford Taurus cold misfire, head gasket problem, last ditch effort

Question
Hello Tim, I hope you can shed some light. For the last couple of days I've been trying to diagnose a 2001 Taurus 3.0 SEFI misfiring condition only on cylinder #1 that only occurs for about 30 to 60 seconds after start up. The problem is worse on cold starts, but also occurs after the vehicle has sat for about 30 minutes. The misfire is slight/random with the the trans in park or neutral, but turns to a dead miss as soon as the vehicle is put into gear. I have performed cylinder leakdown testing with no abnormal leakage found (no cracked head or blown headgasket). The spark plug wires are brand new (genuine Ford), the spark plugs are near new autolite platinum. I have switched plugs to different holes with no change and  checked ignition output with a spark  tester during the misfire (spark is "flamin"). I also checked the injector and CKP waveforms at time of the misfire which look good. Just to rule it out, I swapped injector positions (cyl #1 for #6) with no change (still missing on cyl #1) As a last ditch effort I unplugged the EGR vacuum hose again with no change. Last tid bit of info - during the misfire my scanner is not detecting a misfire, although on 2 previous occasions a P0301 has set. Bizarre! Have you run into this before??  Any idea's will eb greatly appreciated. Thanks in advance  

Answer
Dave,

I hate to tell you, but I still think you got a head gasket problem here.  If you have access to a bore scope I would let the engine cool off and pull #1 spark plug and look directly into the cylinder for coolant. Otherwise maybe a clean white cloth on a screwdriver down the hole and look for coolant on the cloth.  

I have seen engines pass a cylinder leak down, but still have a head gasket problem. The Taurus 3.8 was good for blowing head gaskets, but the 3.0 is usually ok.

The only other thing I can think of would be a leaking valve guide seal filling the cylinder with oil. If that is the case you should see carbon build up on the plugs.