Random Stalling

[sk8]

I have a automatic 1989 325i convertible. It keeps on stalling randomly, and I have no clue what can be causing it.
The car can run for a week without a single problem, and then stall 10 times in one day.Lately it's been doing it a lot more.

The parts I put in trying to fix the problem:
Crank position sensor
Idle control valve
Throttle Position sensor
Vacuum hoses - no more vacuum leaks in the intake
Coolant temp sensor
Cleaned Injectors
Spark plugs
Distributor Cap & rotor
Fuel pressure regulator
Fuel pump
Fuel filter

I also tested the fuel pressure at the fuel rail
~41 psi, ~50 with the vacuum hose unplugged from FPR
On the FPR it's ~10psi, ~7 with the vacuum hose unplugged.

Tried doing the stomp test many times, never got it to work. I know for 100% that the TPS works.
Taken it to a shop twice with this problem, both times they wanted to replace fuel pump, filter, distributor cap & rotor.

I replaced that, and took it to them again, and they said the same thing. I feel like they are just lying to me, only other shop that's close to me is about a hour and a half drive away.

Looked at the spark plugs and they seem fine to me.
http://imgur.com/aaxMrpf

The car will stall if the rpm is below about 1000, but if I'm driving down the road it just drops and jumps back up. Here is a video of the problem.

https://www.youtube.com/watch?v=mLJVLsWslTQ

If anyone has any idea on what could be causing this problem, or how I can diagnose it, let me know.
Thanks!

[glnr13]

AFM? vacuum leaks?

[sk8]

AFM? vacuum leaks?

Intake boot, vacuum hose from valve cover, the one from idle control valve, all were replaced. The ones on the other side connecting to the intake seem fine. Just realized you can test the AFM, will do that tomorrow. If that is bad is it worth it getting a new one? $490 for a new one, for a few hundred more might as well get a megasquirt PNP, remove the maf, and use a IAT sensor.

Thanks for the reply!

[dnguyen1963]

Replacing the hoses without doing a smoke test is not a sure way to prove that you have fixed all the vacuum leaks. Look up some DIY smoke machines and make one for yourself since the shops are too far away.

[sonomabimmers]

have you tried the ECU relay and the fuel pump relay. my car used to just shut off randomly while driving kind of like yours and i replaced a bunch of fuel stuff tried a million things only for it to be a little 20$ relay hasn't died since then been weeks. give it a try might just help you out good luck. if the relay is intermittently working then maybe it shuts off drops fuel pressure and then relay starts working again and boom your back.

[sk8]

Replacing the hoses without doing a smoke test is not a sure way to prove that you have fixed all the vacuum leaks. Look up some DIY smoke machines and make one for yourself since the shops are too far away.

I did a vape test, didn't find any.

[sk8]

have you tried the ECU relay and the fuel pump relay. my car used to just shut off randomly while driving kind of like yours and i replaced a bunch of fuel stuff tried a million things only for it to be a little 20$ relay hasn't died since then been weeks. give it a try might just help you out good luck. if the relay is intermittently working then maybe it shuts off drops fuel pressure and then relay starts working again and boom your back.

I think it was changed a few thousand miles ago, but I will try this.
I was recording the fuel pressure and revving the car a little, and got lucky and had the car stall on video.

https://www.youtube.com/watch?v=K4uN_87w93M

Looks like the fuel pressure drops, would that relay be able to cause this?

[ahlem]

If you lose power to your fuel pump it would cause this.
If you can hook a multimeter or light bulb in line to your fuel pump to see if you are losing power, it would show when it cuts out.