Engine misfire/judder at idle.

[Mike M]

This is getting a bit concerning now. I'm running full decat 1 bar BPU. Did have Denso IK22 plugs but replaced with new NGK coppers as part of the fault finding making no difference.

 

http://smg.photobucket.com/albums/v640/mikemajorek/?action=view&current=MOV00393.flv

 

It causes the whole car to judder sometimes idle. I havent really noticed this on the road apart from the odd pop on the over run.

 

So far i've:- stripped each coil pack clip and checked connection tightness. clips are about 1 1/2 years old.

 

Swapped out a coil pack one at a time with a known good one.

 

Swapped out the spark plugs one at a time with new NGK's.

 

Cleaned out the Idle control valve.

 

Its had a recent O2 sensor.

 

Today the local tyre garage said there were no leaks on the exhaust. But I can smell half burnt V power in the cabin sometimes with the drivers window cracked open when booting it. Strange as you cant smell anything under the bonnet and couldnt see any obvious leaks when it was on the ramp.

 

The only issue I know of is the stem seals are wearing but cant think how this would cause this unless one seal was really bad maybe.

 

Cheers

 

Mike

[Mike M]

I did this O2 sensor voltage check today,

 

http://www.mkivsupra.net/vbb/showthread.php?t=35940&highlight=Narrowband+Sensor

 

The readings were going from 0.9V to 0v to 0.9v in a constant loop. The 0.9v reading sounds like its a tad rich causing the popping on idle.

 

Is the reading meant to drop to 0v in a regular cycle?

 

Giving the fact the O2 sensor is only a few months old surely it cant be knackered and something else is causing it to run rich, injectors maybe?

 

Any ideas welcome.

 

Cheers

 

Mike