Warm hesitation

[brp_rlp]

I have a 95 540i, original nikasil. When the car is warm - sitting from 1.5 to 5 hours - I occasionally get bad hesitation for the first 1/4 mile or so. It goes away pretty quickly, but can be severe when it is happening, to the point of stalling once in awhile. I don't seem to be able to replicate the problem, one day it will do it, the next day in the same conditions it doesn't. It doesn't do it if the car has been sitting less than an hour, or if it has been sitting overnight. I only use high-grade, quality gasoline.

Any thoughts as to what it might be?

Brian

[Tiger]

Could be the fuel pump check valve if you have hard time starting... it probably won't show up as bad until you hit a hot day. If so, use E39 fuel check valve repair kit. Much easier and cheaper to repair.

[brp_rlp]

Could be the fuel pump check valve if you have hard time starting... it probably won't show up as bad until you hit a hot day. If so, use E39 fuel check valve repair kit. Much easier and cheaper to repair.

I don't have a hard time starting it, though I do notice the problem seems to be worse when it's warm out.