They should last 200k miles+ with no problem unless there is something inherently bad with the coil paks to begin with. For example, Nissan's with coil paks in the '99-01 timeframe have a known problem with the coil paks and they can intermittently fail without setting off the SES light causing intermitent missing and rough idle; the coil paks themselves often test out ok with static ohm procedures. Presuming the vehicle has been maintained well, you may want to take a look at the EGR system and ensure the passages aren't clogged up and the valve is functioning properly. Other than the standard items (i.e., plugs, injector, dirty throttle body, slow O2 sensor, TPS or related sensors) that may cause intermittent rough idle, the EGR system is often the culprit that is overlooked.
[ February 18, 2004, 04:44 PM: Message edited by: nick778 ]
