youngcow

Hey Guys,

Forgive me if I didn't look hard enough for other posts.
TLDR: car shuts off randomly and bucks randomly, despite replacing a bunch of parts.

For years now the car would buck from 3k to 4k. I just assumed it was the tune because it's on greddy emange, and during this time I've replaced spark plugs and ignition coils. A few years ago I had a tps code, and the car didn't want to drive. I replaced it, metered it to open correctly, then my air pump went bad and I got the bypass chip (because it was cheaper and I mostly use the car for Autox and light track). Then next thing I know the car dies at every stop, I looked like a complete idiot who didn't know how to drive manual despite having the car for 15+ years. I read a thread about injectors, so I went to replaced the injectors and the car just had no power. Eventually I did a smoke test and found that I was close enough, it wasn't injectors but the injector seal had collapsed. Replaced the injector seals the car drives better but still every now and then the idle drops to about 200rpm and it will just shut off randomly when I put it in neutral and the bucking is still there in any gear leading up to 4k. I've replaced the map sensor, cleaned my IACV (even tested with another one), cleaned my throttle body. At this point after years trying to figure this out I'm at a loss. I'm hoping someone can guide me.

Thanks!

windhund116

What ECU are you running now?

Thanks!

RolanTHUNDER

Does it happen when the car is hot or cold or does it do it regardless of temp?

Caden Armentrout

Have you checked what your TPS reading is when this is happening? I had issues with my throttle cable (AP2) from time to time and it would either hang open for a second and or close on its own.

youngcow

It's stock ecu with greddy e-manage piggy back.

youngcow

Regardless of temp.

I would need a second person in the car with me at all times to read the TPS. I can't recreate it on command, it just randomly happens. I have noticed when the car bucks if I shift into neutral and leave it (like when I'm slowing down to stop) the car will shut off.

Thank you everyone for your replies!

RolanTHUNDER

This reminds me of the issue I experienced with an '04. It's the first time I ever saw this on an S2000. It would randomly hesitate and buck at low RPMs at light throttle. It got so bad that it wouldn't want to accelerate until I floored it. When I clutched in it would rev but as soon as I let the clutch out it would hesitate badly. This usually occurred after a short drive to the mall or somewhere. I'd let the car sit in the parking lot for however long so it would cool down a little and when I started her back up this problem occurred. It would do that for a few minutes until settling down. Stock ecu, no mods. I tried different MAP sensors, ECU reset, etc but it never went away. The only thing I didn't try was a spare TPS. I don't have a spare TPS but I think that would be a good test in this case. Not sure if any of the injectors could be sticking that badly but that might be a possible cause

youngcow

I bought a honda TPS and the ballade motorsports s2k one (cause the connection is pointed in the right direction, upwards?) I'm not really sure what to do next

RolanTHUNDER

Have you already tried both of those?

youngcow

Yes sir, currently the ballade motorsports one is in the car. Both did the same thing. The original one threw a TPS code so that one is useless.