running bad
 

hi there i have a 1998 boxster 2,5 73500 miles dont use it much but when i brought it now and then it ran like it was running out of petrol so stuck it in a porsche dealership thay put it on there machine and said needs a new mas so new 1 fitted but car is still doing it any idears please

The standard question is what codes are you seeing. Codes are diagnostic messages to a maintenance computer hooked up to the OBD2 port under the dash of your computer. The engine codes are generally readable via code readers, Durametric SW or the special diagnostic computers dealers use. In the states we can often get the codes read at an auto parts store for free. Or you buy an OBD2 code reader. IS the car stock (as from the factory, no performance mods) as far as you know? Was a Porsche part used for the AMF? If the mechanic installed the MAF (which is actually seldom the real problem) he may not be an expert in Porsche engines or he should be asked to reinstall the original MAF and find and fix the problem. Or go to a real Porsche engine expert.

If you read the codes, post em here and someone will tell you the probable causes.