I have spent about 7K so far trying to figure this out - dealer nor mechanic can figure out - no codes from the system indicate a problem. Car bucks/jerks while driving; a jumping sensation. sometimes barely and then other times harder. So far I have replaced all engine coils, gasket, transfer case, crank shaft sensor!!! UGH. No one knows why this is happening. I really need HELP!!! I am hoping someone out there can help or advise. I can't be the only one to ever have had this issue.