Hey guys I bought a 1999 civic ex and it was running fine. I fill it up and it starts missing. I've replaced plugs, wires, distributor, idle control, throttle position sensor, fuel pump, fuel pressure regulator, and fuel filter, gas cap, number 2 fuel injector.
im getting a gurgle /grinding noise coming from my pump area, and a similar sound coming from the new fuel pressure regulator . The sound is consistent in the tank and only when I start it in the regulator ( it seems).

The misfire
It's only there when the car is at operating temp and around or under 3500 ish rpm. Once it gets any higher the car seems to drive fine, it seems a tad weak on the end of 4th and 5th gear but idd maybe just d16? I'm sometimes get a fuel smell in the car that seeeeems to be coming from the pump but I can't be for sure??

This gurgling noise is a new thing I'm hoping it's whatever was causing my misfire finally giving in and showing itself? Because this has been just a huge pain in my butt... Any help appreciated thanks.

 

Remove the rear seat portion and take a look at the fuel pump. Previous owner may not not properly tightened the cover or hose clamps

 

I've changed out the fuel pump. Everything seems good there has a clean tank and seal. I suspect someone replaced it before because how nice the tank is but idk it's my first time looking in one? I've turned the key over and stared at that thing alot trying to find some kind of leak or smell fuel before it gets to operating temp.

 

It's an aftermarket fuel pump I don't remember the brand but it wasn't making this noise when I put it in a couple weeks ago. The sound I'm hearing almost sounds like a bunch of air getting pushed through the fuel lines with the fuel ? I can't be for certain though. Is there anything else I can change or check? I'm really hoping fixing this finally fixes the miss