Poorly Z4M, Idle bounce and poor throttle response/misfire

Now that i'm a little bit more familiar with my car, i know i also have the problem.
Very noticeable below 2k rpm when the engine is hot. Flooring the pedal from idle will lead to a massive hesitation before going up the revs. When releasing the pedal, revs will drop below idle, to around 500 rpm, then go back to around 850-900 rpm.
Engine oil is new, air filter is good, i just changed the spark plugs for NGK Iridium, it seems that all my ignition coils are good (i didn't take the time to check each coil individually while the engine is running, but it seems to me that all 6 cylinders are firing correctly), i've been using several brands of fuel for the last 3 or 4 tanks (Total, Elf, BP, Esso).
I don't have an "oiled" filter on may car, but he previous owner might have had one.

Since the problem seems to be located around idle, i'll be inclined to think that the idle control valve is the culprit. But it is a bit of a PITA to get to it on the S54, much more than on my previous M54 engine...

The car will soon be booked for some work at an indy shop (valve clearance + transmission fluid change), i'll ask them to get a look at it.
 
My TT had a failing lambda sensor and some days would drive like an old dog, whilst on other days it was fine. Lambda sensor failure has been common amongst ///M owners, and I too suspect that in some cases this could be contributing. ga, did you replace all of the sensors, or just one?
 
IIRC there are four lambda sensors, (two pre- and two-post cat). Is yours now running ok? If not, do you think there's anything to be gained by replacing the other two?
 
Yeap there are two more on the catalytic converters but the mechanic deemed them OK and did not order those. The car is running good at the moment. The hesitation is still there but not even close as noticeable as before and the dip on idle is now gone.
 
ga41 said:
Yeap there are two more on the catalytic converters but the mechanic deemed them OK and did not order those. The car is running good at the moment. The hesitation is still there but not even close as noticeable as before and the dip on idle is now gone.
Click to expand...

How long has it been running well after the o2 sensor change and did the mechanic reset the adaptions?
 
The mechanic reset everything. All adaptations, throttle pedal etc. The car's been back for about 3 weeks now.
 
My car reacted similarly after a full reset. Initially it ran really well but then the ecu started to make adjustments for whatever sensor is not working properly and the problem gradually started to come back.
 
Very rarely mine will do a little dip of revs/hesitation when suddenly on full throttle in second gear before all hell breaks loose and I am fired down the road like and Exocet missile. Only very rarely like maybe once every couple of months on a regularly used car. In all honesty I think it's a characteristic of the engine.

It has never stalled however and so this maybe different to the OPs problem.
 
anyone running speed density tune / aplha N get these issues??

wondering if they are mostly mass airflow related.....
 
This thread has gone way over my head since I commented on it early on. My answer is sticking to BP Ultimate and all seems ok here.
 
Ruby, I just put in Tesco 99 and got the emmissions light half way through the tank, next tank filled with BP ultimate and light went out. Lol
 
RubyBlueZ4MC said:
This thread has gone way over my head since I commented on it early on. My answer is sticking to BP Ultimate and all seems ok here.
Click to expand...

Mine still seems happiest on the BP Ultimate fuel, Shell vpower brought back the idle dip/splutter when I tried it recently. Perhaps my o2 sensors are not at their best (36k miles).

Somedays it feels much perkier than others.
 
I put shell super unleaded in my car the other day, not really noticed the difference or does it take a few fills to notice the added benefit of the 20-30 bhp that someone meantioned somewhere on this forum :roll:
tht would be like adding a tuning chip to the car?
off topic slightly

does anyone car start up after varying amounts of time? im not talkin ages, but when i first got it i turned the key and one second later it was up and running, y'day it seemed to take two seconds and today its close to that
yes i know its not a massively big deal...just wondering if its normal for the car to sometimes "struggle" for a second or two, i kno its slightly more specialist than my 2.0 but just posing the question, seeing as its in warrany time i'd like to get out any possible issues while i can :thumbsup:
 
Mine takes a good 2-3 seconds to fire from cold, slowest car i've ever for starting up. Warm starts are quicker.
 
I managed to solve that with Liqui Moly injector Reiniger / Ventil Sauber.
Here's the thread:
http://www.z4-forum.com/forum/viewtopic.php?f=9&t=37442
 
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