If the idle isn't smooth, check the MAF. Mine needed a clean before 20k miles. It was slightly oily, and a squirt of cleaner fluid resolved it.
Worth checking,( especially with K&Ns).
Thanks Dave, MAF has been cleaned, and then changed. Also cleaned the IAC valve, changed standard air filter and spark plugs. Next up will be the leads. I've had all manner of additives put in the fuel to clean the injectors also. It's not an issue as it never stalls, just when you are used to a perfectly smooth running engine in the tin top, it's just a bit irritating.
