If you are sure all the relevant tune up items are correct, I would be doing an exhaust gas analysis.
If you see a higher than normal reading on the hydro carbons you may have a problem with an injector, you can have a injector service done on car"it is a good idea to think about this every few years as they are often forgotten about completely. Also a skilled operator will be able to read a live data read via a hand held good quality scanner, this may show up something. If there are NO codes set (you have checked?) You don't always have a fault light on with a set fault code. Also check things like valve clearance's coil out put voltages, High tension lead resistances, and get a run on a oscilloscope, as that will be able to do cylinder balance checks, check KVa's and ignition pattens, all helpful in diagnosing tune faults,
Sunday, December 9th, 2007 AT 8:41 PM