Is350 Cuts Out Badly At About 2500 Rpm

[marzx]

My IS is cutting out badly at about 28-2900 rpm, it accelerates properly up to that point then falls flat like the fuel is gone or ignition is gone.

It was in a passenger side accident a while back and has done this ever since. The Lexus dudes have told me many different stories from it sitting too long before driving again to a cut-out switch being tripped in the fuel system which they can't locate or reset.

The only thing they have not replaced is the in-tank fuel pump (I looked at a different IS and disconnected the line to the mechanical pump on the engine and the tank pump held fairly good pressure when the car was not running, I noticed mine does not hold any pressure to the mechanical pump when engine is off. I don't know if this has anything to do with the problem.

Anyone out there know this system well enough to speculate??

Thanks

M