What would cause come and go hesitation?

I recently had the maf replaced and it seems that the hesitation gradualy worsens as the car gets wormer. Ok to start I own a 94 3000gt sl. I have it to the garage twice doing things like shocks struts starter, and had everything checked out. It seem like when I drive it more then 20 min it starts hesitating(bucking) under medium throttle and it worsens over the course of the next 5 miles until and throttle causes hesitation and I have to shut her off. There is a very rich smell only when it acts up. The weird part is when she acts up and dies on me I limp her home and come back out the next morning and she fires right up and runs good. I have also had the lifter tick so I flushed the oil and started running fully synthetic( which she loved) but I still have the tick and when im in stop and go traffic she smokes so I think my vss are bad. The other symptoms are when she starts up with symptoms I notice that she idles at 600 and has no power when u rev it, backfires and makes a popping noise through the intake. Replaced maf sensor with no luck please help!