1984 318i bmw loses power when accelerating

[Nickb2105]

So I have a 1984 318i 5 speed manual I have replaced the MAF sensor, fuel filter, fuel pump on the fuel line, new tps sensor, new cap and rotor for distributor and they all helped and seemed to make the car run better but there’s still one problem when I drive it it will start right up and drive like normal then randomly I will go to accelerate and when hitting the gas pedal it will make the rpm’s drop and when I keep my foot on the gas it will make the rpm’s drop then stall out start it back up and does same thing. If I let it sit for a min or 2 and try to drive it again it’s fine and will drive like nothings wrong. I’ve checked for vacuum leaks all hoses are new and no cracks or leaks, did compression test that’s fine, did fuel pressure test and was getting around 45-46 psi, checked to make sure I was getting spark and it was fine, cleaned the injectors. I’ve been trying to figure it out but no luck and don’t wanna just start throwing parts at it so I need some help if anyone knows what the problem could be lmk.

[Nickb2105]

I also replaced the fuel pressure regulators, and spark plugs

[82eye]

So I have a 1984 318i 5 speed manual I have replaced the MAF sensor

there is no maf sensor on an 84 318i.

there’s still one problem when I drive it it will start right up and drive like normal then randomly I will go to accelerate and when hitting the gas pedal it will make the rpm’s drop and when I keep my foot on the gas it will make the rpm’s drop then stall out start it back up and does same thing. If I let it sit for a min or 2 and try to drive it again it’s fine and will drive like nothings wrong. I’ve checked for vacuum leaks all hoses are new and no cracks or leaks,

bogging usually traces back to vacuum. i'd smoke test to double check. aside from hoses often it is something not thought of, a poor seal on the valve cover oil cap can do it, or deteriorating seals on the intake.

smoke test is where you want to go next.

[323i E30]

I have a feeling it’s more of an electrical issue. Especially because it comes and goes like that.
Do you see the rpms on the dashboard drop quicker than the actual engine speed?

82eye may be right of course, but this would be a pretty extreme reaction to a vacuum leak.

[tomstin]

You may want to pull the fuel pump and look inside the tank for debris. It's not uncommon for rust and junk to build up in the tank of these old cars. After running, typically highway, the sock on the end of the pump clogs. Once the car sits for a bit, the debris falls from the sock. More common as the fuel gets lower in the tank.

[akimball442]

Install a fuel pressure gauge and go for a ride. That'll be the easiest way to figure out if it's fuel or ignition related.

Another quick check could be to disconnect the throttle position switch. If it's sticking closed, it'll think it's at idle and may not give you the increased fuel needed to accelerate.

[Nickb2105]

You may want to pull the fuel pump and look inside the tank for debris. It's not uncommon for rust and junk to build up in the tank of these old cars. After running, typically highway, the sock on the end of the pump clogs. Once the car sits for a bit, the debris falls from the sock. More common as the fuel gets lower in the tank.

I just saw this post before I read it earlier today I took the in tank fuel pump out because I already assumed it was that and there was debris and rust which I kinda assumed and found that the wire on the fuel pump was broken off from the connector thank you for your help ima order a new one off rockauto asap

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I realized whenever it cutout I hear the fuel pump on the line start to get louder so I’m assuming whenever that wire moves and loses connection the fuel pump on the line strains it self to get fuel to engine while the other one in the tank don’t work

[Nickb2105]

I have a feeling it’s more of an electrical issue. Especially because it comes and goes like that.
Do you see the rpms on the dashboard drop quicker than the actual engine speed?

82eye may be right of course, but this would be a pretty extreme reaction to a vacuum leak.

So what happens is when it occurs and I hit the gas pedal the rpm’s will drop if I stay on it if I let go they will go back up and it won’t increase in speed or decrease instead of the gas pedal increasing Rpms it makes it shoot straight down

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What I’m thinking is the fuel pump isn’t working caused by that wire being broke and when it happens hitting the gas will make it take in air but since no fuel is getting to the engine it just shuts down cause there’s only air in the air fuel ratio