Help me load the parts cannon, beater P10 content.

1991 Infiniti G20.  Hit a 2x4 on the highway and the car hasn't run right since.  Starts and idles fine but will not accelerate past 50-60 mph once in gear, sometimes not even that fast.  No visible damage to any systems or wiring.  Checked fuel pressure with a gauge teed into the supply line, and while it's fine at idle, once you open the throttle it drops off to nothing.  As you close the throttle, as it gets closer to closed the fuel pressure picks back up again.  The fuel system does not hold pressure after you shut the car off. So, i think i have a failing fuel pump or bad check valve in the pump.  My plan is to replace the fuel pump. strainer, fuel pressure regulator and fuel pump relay. Should I add a TPS?  Is there anything i'm missing?  It's my work beater, and while i can putter around town in it as it sits, i'd really rather have it in proper running condition.  Open to suggestions before I hit up rock auto.

Make sure the tank isn’t dented where the pump is located.

Never throw parts at it if you don't know they are definitely needed.  You run a high risk of introducing new problems.

My gut reaction is that somehow the main fuel feed line got pinched off.  It would have to be a hit so hard that you'd see floor bucklage though.

My second, more introspective thought, is that it banged the bottom of the fuel tank hard enough to damage the fuel pump somehow, possibly splitting the line between the pump and the top of the sending unit.   I've seen that failure before due to age, and it does indeed result in poor fuel flow and rapid pressure bleed-off with the key off, since you now have a sizable fuel leak between the pump and regulator.  Of course at that point, you probably have a new pump in hand, and fuel pumps are wear items, so you may as well replace the $300 fuel pump while you're in there replacing $.50 worth of hose.

I wouldn't touch the TPS - it wouldn't have anything to do with the issues you are having whatsoever.  Focus on the immediate issues, not straws to grasp.  Same for the regulator, if it ain't broke then wrenches only make it worse.  It IS a good idea, however, to replace the fuel pump relay at the same time as the fuel pump, since the contacts do get burnt up over time.  (Or if you're cheap, replace it with the horn relay or something - the fuel pump relay has thousands of hours of use, the horn relay has seconds)

If you want to verify the fuel issue is not the regulator, find a rubber return hose, get the car to where fuel pressure has decayed, and pinch it quickly with some pliers.  No change means the regulator isn't the problem.

In reply to Knurled. :

Got it,  It's a plastic tank, but it did take a pretty good hit so i'll pull the pump and sending unit and check the lines.  I did the pinch test with the return line off the regulator and there wasn't any change.  Was going to replace the regulator out of caution but if it ain't broke don't fix it will be my rule of thumb here.  I didn't notice any floor damage but i will check the feed line because reasons, usually the last thing I think to check turns out to be the actual problem.

And for $300 for a fuel pump, I would be looking at a decent inline pump that can sit outside the tank. Draw through the old pump. Simple, and you may not have to drop the tankto do it. 

Knurled nailed it.  The bottom of the tank took a hit and pushed the fuel pump cartridge up a bit which put a kink in the line between the pump and the sender.  The tank is under the back seat and has an access panel so checking the pump and sender is easy peasy, no tank drop required.  Replaced the kinked line with a piece of submersible line i had laying around.  Cut it to fit without kinking and put it back together.  No more pressure drop and now it revs out to the limiter.  Putting the parts cannon away, but I am getting the Beck Arnley fuel pump kit with strainer rock auto has for $17 for when the el-cheapo one that's in there now dies.  Thanks Knurled! 

In reply to _ :

Still have to access the old pump to fix the hose inside the tank. I have seen multiple failures such as Knurled described above.

I se OP has it fixed. Good job

In reply to 06HHR :

I've been waiting to use this for years!