I have a 2004 roadster that developed this sudden problem. I checked the air filter, no problem. Then pulled all the plugs. When I got to the rear cylinder (driver's side) and pulled the coil, I saw that it was soaked in oil which was about half way up the spark plug well. After getting out as much as possible, I pulled the plug and it obviously hadn't been firing. Cleaned up as best I could, replaced all the plugs (normal), put back together and SAME PROBLEM! Think the coil is shot?

 

Yes, the coil is "done for." You should be able to get a code verifying this.

 

Look into the Factory Service Manual on the testing procedure for coils. You could swap a coil from a known working cylinder to the dead coil cylinder to see if the problem is the coil or something else within the cylinder.

If you need a single or a few coils to replace this one let me know -I've got a few extras I'll either give you or sell you for next-to-nothing.

 

 

Thanks all for the comments. I at first thought that the oil was in the well because the last person to install plugs really cranked that particular one down, hard.
The car has like 49,000 miles and change but it IS 14 years old. May be a gasket. I suppose that I can go through pulling that plug again after I drove it maybe a mile and see if there's oil in the well. If no, probably dead coil, If yes, dead coil plus ???
Will have it checked out and report back what I find in case somebody else has a similar issue.

 

The spark plug seals (molded into the valve covers) are notorious for leaking on these cars. Do a little reading and you will find there are quite a few options available for the DIY'er.

 

Thanks Lex. I'll do my reading.

 

My 05 roadster was not misfiring, but while in the middle of replacing the valve covers, I noticed that my driver's side rear spark plug well was filled with oil. Like another member mentioned, you must replace the valve cover, which has the molded spark plug seals. There is a fix for it where you drill out the seal or something, but its not worth it IMHO. It is better to replace the valve covers (do both).