hi i have owned my 16v for about 2 weeks now,its in mint condition with full service history,its done 100,000 miles now its k 1993,when i first start it,it sounds really rough and tappy but give it a couple of mins and let it warm up and it sounds fine,should i be worried?is this bad?should i think about an engine rebuild?i love this car and i want to own it for quite a while and do plenty of mods to it,can any1 help? thanks!!