Strange behavior but no code, should I worry?

[wawa]

I just receive my short shifter so I did a trip with my 2000 Boxster S to buy some lithium grease to install it. Well during the trip, the Boxster hesitate a couple of time when accelarating (not hard). I stop at the shop, bought the grease then drove back using the highway. While accelerating harder to enter the highway the Boxster nearly died but as soon as I let go the gas, it was good again. I was able to accelerate normally. I try again a little harder acceleration and it was ok. When exiting highway, put the clutch down and engine simply died. I stop on the side and restart it, no problem, idle fine and was again able to drive normally to home.
This morning I took the Boxster for another trip to the shop to by a code scanner, some MAF cleaner and Throttle body cleaner. Everything look fine, idle and standard acceleration. Did not try hard acceleration. Not CEL no nothing.
I have check for code, nothing pending. Everything looks fine. Should I be worrying?
As you guess I will clean the MAF and the Throttle body in prevention. Never done it since I own the car about 1 1/2 year ago. Air filter is new, that its.

Thanks
Chris