Juddering/Surging under power

Post Sat Jun 03, 2006 1:37 am

I noticed today that my car was surging under power, at most speeds. It almost felt like a transmission problem, like there was something slack in the drivetrain preventing a consistent power delivery. Has anyone come across this before, its only very slight, but VERY annoying?

Post Sat Jun 03, 2006 1:53 am

Had it before - and it was the O2 sensors (was on an e36)

Post Sun Jun 04, 2006 11:05 pm

thanks mate, has anyone else had experience of this?

Post Sun Jun 04, 2006 11:18 pm

Only flaw in this theory, is that most E30s don't have O2 sensors.

Post Sun Jun 04, 2006 11:27 pm

Mine does Brian, or at least I assume so, this is the lamda probe in the manifold is it, or not?

Mine has a cat so if so then that might be the problem?

Post Sun Jun 04, 2006 11:33 pm

William wrote:Mine does Brian, or at least I assume so, this is the lamda probe in the manifold is it, or not?

Thats the one

You cant always check it by testing it (the e36 bentley manual covered that - could be the same on the e30?)

Post Mon Jun 05, 2006 12:21 am

William wrote:Mine does Brian, or at least I assume so, this is the lambda probe in the manifold is it, or not?

Mine has a cat so if so then that might be the problem?

If yours is one of the few (in UK, at least) that has a cat and O2 sensor, then surging is indeed a symptom of a failing lambda sensor.
Get a meter on it's signal output wire. Should be switching between positive and negative, and at a rate of faster than 2 Hz.