Right guys and girls, I need some help diagnosing an ‘unusual’ fault with my Zed.

 

The issue is that when breaking (e.g. coming to a stop at traffic lights) the revs drop to the point where the car cuts out. This is also noticeable when shifting from neutral to reverse (automatic) as shown in the attached video.

 

[video=youtube_share;Q5uJ3az3pLc]

 

The rest of the time it seems to run fine although I’ve noticed that if I’m coasting along and lightly touch the throttle, the revs drop down (below 500rpm) before climbing as I press on the accelerator.

 

So far I’ve have a vacuum leak test and there’s no air leaks. Also had the codes checked which returned a code with CAS, although I’ve been told these rarely break. The IACV has been tested and I’ve been told has been performing as expected.

 

At this point I’m looking for suggestions on what to check next, as google has suggested everything from the brake booster to the MAF. If anyone had come across this issue before and has some pearls of wisdom I’d be grateful for any input.

So i somehow managed to hit enter when trying to edit the title of this thread.

 

Can an admin please change the title of this thread to 'Idle Issue - Revs drop and engine cuts out when braking'

 

Alternatively I'm happy to change it myself if someone can explain how...

TPS? That can do funny things at small throttle positions.

 

If it were a manual I'd wonder if the clutch was dragging, so whatever the automatic version of that is, bad oil... bad torque converter.

 

The little I think I know about automatics, is that they are sensitive to the quality of their oil, good and bad.

 

I’ve noticed that if I’m coasting along and lightly touch the throttle, the revs drop down (below 500rpm) before climbing as I press on the accelerator.

 

 

I had this when mine was an auto, local garage cleaned out the throttle body for me and never had it happen again.

I had exactly the same issue with mine and it drove me nuts...... Till I fitted a new throttle position switch/sensor.... mine had a fault on the switch part inside and not the potentiometer part (comes as one unit)...

I had a few near misses when slowing down to stop at lights and nearly rear ending people when the engine cut out and no steering or brakes.....

As Tom said....... lol

 

Also, have you had the transmission fluid level checked?

This is done with fully warmed up transmission, flat level surface and dip the transmission fluid whilst idling in neutral..... do you have a copy of the workshop manual?

 

Hope this helps....

Edited November 15, 20187 yr by veilside01702

When you say braking - do you mean a slow, smooth gradual glide to a halt; or a more swift slow-to-stop in the last few metres?

 

I may have dreamed this, but I vaguely remember that failed PCV valves can be the cause in the latter circumstances.... Oil from the top of the engine can get into the throttle bodies during (ahem) enthusiastic braking; thus temporarily messing with the air-fuel mixture.

When you say braking - do you mean a slow, smooth gradual glide to a halt; or a more swift slow-to-stop in the last few metres?

 

I may have dreamed this, but I vaguely remember that failed PCV valves can be the cause in the latter circumstances.... Oil from the top of the engine can get into the throttle bodies during (ahem) enthusiastic braking; thus temporarily messing with the air-fuel mixture.

 

And if I have just made that up, please do forgive me.... Getting senile in my old age...:lol:

You'd really have to be going some Richard! :lol:

 

To the extent that the main thing messing with your throttle bodies, would be the driver of the car in front!:taz:

Thanks for the replies all.

 

Think I've decided that I'm going to clean the throttle bodies and break out the multi-meter tomorrow. I'll all put the ATF fluid on my to-do-list while I'm at it.

 

As for my 'style' of braking - I wouldn't say that I'm particularly hash, especially while i reacquaint myself with Zed brakes :pinch:

 

I had wondered if braking has anything to do with it, and had made a point of braking early (really early) to see if that would prevent the revs from plummeting. It didn't seem to make any difference and i still found myself trying to blip the throttle to keep the car alive, while praying the car behind me doesn't go up the back of me...