damn i wish someone with some real smarts would reply in here, cuz im goin out on a limb. but id say if youre concerned about the timing being off check it out. it doesnt take much to make your car run like shit if your timings off a lil. i know for a fact that some of the shops dealerships run their cars through are hacks. you should have your own trusted mechanic that you deal with right? have him double check the work that was done.