Several mornings in a row I've noticed the engine in my '03 MCS (6 speed, 140k miles) has an obvious "miss" when cold. The problem goes away in a mile or so as the engine warms up, although this morning I drove about 15 miles before it went away. The weather here in New Jersey has been humid for several days, so I'm thinking it might the ignition cables (I think they are the original set) absorbing moisture, and the moisture dissapating as the engine compartment warms up. I was also thinking ignition coil, but don't coils tend to fail as they heat up versus when they are cold? The plugs have only 40k miles, but I'll pull them out and have a look if I have to. I searched all the forums, and the only other idea I saw was to try a bottle of Seafoam or Techron, but if that was the issue wouldn't my engine have the miss more or less 100% of the time? Has anyone else here experienced a miss that went away as the engine warmed? What was the fix? Any other ideas? Thanks in advance for your help.

 

Sounds like you need a tune up. Plugs, air filter, wires, just the basics an 8 year old car needs at any mileage. Really until you do that, I wouldn't bother with anything else.