2000 Z3 poor acceleration

[ScottZed3]

2000 Z3 2.5L roadster. EML light and traction light are on. Changed throttle body for a P1850 code, cleared and not came back on. But starting out idles fine, go to accelerate and very slow to accelerate and max RPM is about 28-3000 rpm @ 55 mph max. Starts to pick up at the start of each gear like its gonna take off but then falls on its face. If you feather the pedal it will slowly pick up speed, but 55 is as fast as it'll go. I'm new to BMW so any help will be appreciated.

[Raddee]

If you don't have a check engine light then your ignition is probably fine, so then I'd move on to fuel issues. Has the fuel filter been replaced recently? I'd start by preemptively replacing that, it's a good idea either way. If that doesn't solve it, check fuel pressure at the injector rail.

Does it rev further than that in neutral? If it does the same thing in neutral then it might be a sensor issue, if it does rev further then it's most likely indeed a fuel pressure issue.

I've also seen a similar issue on a car that had the inside of the catalytic converter rumbling around freely inside and clogging up flow through the exhaust, but that also came with loud screeching noises out of the exhaust, so unless you're hearing that it's unlikely..

[MarcoZandrini]

The Service Engine Soon (SES) light is on inlybwhen a emissions related code is present. Rescan the engine computer (DME) and report back. Is the fuel pump original? When was the fuel filter last changed?

[Muzz258]

The Idle Control Valve controls the revs of the engine up to around 2,500 rpm, then the throttle body kicks in. It sounds like the new throttle body is not working. Check that the plug has been installed correctly on the throttle body.

[Raddee]

The Service Engine Soon (SES) light is on inlybwhen a emissions related code is present. Rescan the engine computer (DME) and report back. Is the fuel pump original? When was the fuel filter last changed?

(Big) Ignition problems will always trigger CEL because they can cause unburnt fuel to reach the catalytic converter, causing damage and more emissions as a result
On the E46 also the DME will stop fuel injection to a cylinder with ignition issues until the engine is restarted to prevent this.