my jeep cherokee i bought used 3 months ago and when it ideals the jeep shakes. when its warm when u push on the gas it hesitates like a coil is bad. but it doesn't do it all the time. If you really get on the gas it feels like it goes into neutral. it is a 4.0 automatic 4x4 sport. I gave it a full tune up including transmission fluid change and filter. Cleaned all the grounds.