Random engine stalling and choking issue - no DTCs, Service Engine light on
 

Hey!

Once a month or so, my car starts experiencing issues with the gas pedal response - it just chokes and shuts off. Typically, rapidly pulsing the gas pedal is the only way to restart it. Otherwise, it just cranks without turning on. When it does restart, the car continues to choke for about 10 seconds before suddenly responding normally to the gas pedal, with the RPMs shooting up. It then functions smoothly for about another month. This issue occurs randomly, irrespective of whether the engine is cold or warm, and no matter my driving style.

Unfortunately, this time the usual fix didn't work. Even after over two minutes of pulsing or fully depressing the gas pedal, the car continued to choke and wouldn't fully start, as you can see on the video - when the pedal is red, it means that I'm fully pressing it. Once I stop engaging the pedal, the engine dies immediately and the "Service Engine" light comes on, though no DTCs are being reported.

From my checks, the throttle body is operational as evidenced by the boost meter behavior: creating under-pressure when I release the gas pedal, and pressure equalizing with the atmosphere (0 bar) when fully pressed. Both MAF sensors and the throttle body were thoroughly cleaned about two weeks ago, which didn't resolve the issue. The fuel pump also appears to be working correctly, as it remains audible during these episodes.

Any insights on what might be causing this problem? I eventually managed to fix it by holding the gas pedal depressed and allowing it to choke for like 5 minutes straight - suddenly, the RPMs shot up and I could let go of the pedal, which is the usual fix, but this time it took a few minutes instead of just 10-15 seconds.

Relevant mods: Vortech V-3 Supercharger, Stillen fuel injectors, A2A, no cats, custom exhaust.

https://youtu.be/mDEBxW7wyts

Generic OBD 2 scan tools won't always be able to read all codes. With that said if you have fuel and you have air the last thing is to check the spark. Coils and plugs. See if you can take it somewhere with a good scanner tool, could save you some time and money.

Apologies for reviving this thread, but I've finally identified the issue. Based on your suggestion, I replaced the spark plugs, as they were due for replacement anyway, and inspected the coils. Unfortunately, it didn't fix the problem, and I dont' have access to a professional scanner, but it wasn't severe enough for me to act immediately, so I chose to live with it for a while.
Starting around November / December, the frequency of stalling increased significantly. I decided to replace the fuel pump and ordered a new DeatschWerks 340lph along with an OEM harness. When I removed the old one, it turned out that the pump was completely loose within the harness body. Nissan's design for installing a fuel pump is incompatible with many aftermarket pumps due to their larger size, so the previous owner had to cut the lock-in mechanism off the harness to make the installation work. Unfortunately, they failed to create a secure alternative, or if they did, it clearly wasn't effective.

My theory is that when the pump started drawing fuel, the resulting vacuum caused it to stick to the bottom of the housing through the filter. This would explain why the issue often occurred on rough terrain, where vibrations likely caused the pump to shift and get stuck temporarily. Curiously, this issue cannot occur with the OEM pump, even if it detaches from the lock mechanism. The original particle filter includes a plastic component that maintains a gap between the bottom of the filter net and the pump nozzle, preventing it from sticking to the housing. To be clear, I'm not sure if this net is even supposed to act as a filter or just a fuel "collector", but that's not important.

I resolved the issue by installing the new pump and harness, using fuel-resistant adhesive to secure it in place. Since then, the problem has been completely eliminated.

Some manufacturers include an elastic sleeve designed to create enough friction between the pump and the housing to prevent it from sliding down. However, considering the strong vacuum at the bottom of the pump, I'd recommend adding a strong fuel-resistant adhesive or creating a proper lock-in mechanism that would provide a more reliable and long-term solution.

Here's how it looked: https://imgur.com/a/0mfE5xo

Interesting, I used the aftermarket foam sleeve and had to basically press the pump in place.

I can see the foam getting deteriorated (especially with E85) and the pump slipping down.

Thanks for sharing.