Runs! for 100yrds

[rt325]

Bought this one as a dead 318i.  Found many problems, Fixed somethigs that were fine and eventually I have gotten it to run.   Re-assembled everything take it out of the the garage for a drive and it goes about a hundred yards and then dies. The revs start dropping ever so slowly, you matt the gas and it does not rev, just steady dropping, feather the hell out of the gas and you can get it some gas, but still steady dropping?  By the way once it restarts usually 20 min's later it will idel with no problem.  Get on the gas and same process over and over.
Ideas???:confused:

[3bvert]

fuel pump or restrictions, filters etc
my first thought anyway

[Ramblin MAn]

+1 what 3bvert said. I would also check the fuel pressure regulator. Get a fule pressure guage and put it in line up by the  rail and see what kind of pressure you are getting