problems with chevy suburban?

[shasha12341234]

2001 suburban starts fine , when put in drive goes about 50 yards and starts to sputter and die out, but when put in neutral saves it from dying and even then after a while once it heats up sputters and sputters untill dies in neutral. ive replaced fuel pump, fuel filter, spark plugs, and fuel pump relay
and have checked feul pressure regulator. pressure on fuel rail is between 45 and 50 where it should be. the 2001 suburban has individual coil packs for each cylinder