In this service, repeat the 32,000 mile service, but do some additional things as well. You need to replace the spark plugs, replace the rear drive assembly fluid, replace the power transfer unit, and change the automatic transmission fluid. The latter is especially important if you use your Grand Cherokee to tow things often. 96,000 Mile Service Jun 15, 2010 · 16 Spark Plugs (2 per cylinder) 8 Separate, Dual-Secondary Output, Ignition Coils. 2 Knock Sensors. Powertrain Control Module (PCM) Also to be considered part of the ignition system are certain inputs from the Crankshaft Position, Camshaft Position, Throttle Position, 2 knock and MAP Sensors. Discount prices on Jeep Cherokee Spark Plugs for Model Years 1974 - 2015. Free Shipping & One-Year Lower Price Guaranteed. Shop online or Call 800-544-8778 to order today. If you own a 1999-2010 Jeep Grand Cherokee, and your 'Check Engine' light is on, you can easily check for Diagnostic Trouble Codes wikiHow is a "wiki," similar to Wikipedia, which means that many of our articles are co-written by multiple authors. Change Spark Plugs in a Renault Clio Mk3.