If you have a 3.1L 1994 & older with the coil packs under the front exhaust manifold. Front cylinders are 2-4-6, back cylinders are 1-3-5. coil packs left to right are 1-4-6-3-2-5. If you have a 3.1L 1995 & newer with the coil packs on top of the engine. Front cylinders are 2-4-6, back cylinders are 1-3-5. coil packs left to right are 5-2-3-6-4-1
Rob The backyard mechanic, March 2006