Intermittent cut

[Guest]

Other day driving to work started to get a slight ignition cut kind of like a real mild launch control type thing. Ended up really bad and its been in garage since but for one drive. Once it got about half temp so warmish 60deg odd it started to edge in again then turn into the full blown cut like youve dropped a coil but all 4 not 1. It would slip out of it and run right for 1.5sec every 20sec or so. When cutting it fluctuates between 15-16.5afr and target/normal running is 14.7-15ish.

Just started it now and it had a rough patch but very subtle about 60deg again then cleared and is idling/revving perfectly.

V7 mani/TB with G4, 840cc, iridium 7\'s and V9 cop running wasted spark.

So far Ive tried:

Cleaning earths

Checked plugs a few times - all look mint not fouled or too lean, gaps .625

No fuel leaks

Flexed the wire from each COP to the firewall and checked connectors

No leaks post TB

Calibrated MAP

Pulling injectors to check for a difference

Nothing hinky in runtime values or error codes

Nothing made a difference or helped. Doesnt sound like plugs but might throw the coppers back in anyway theyre not half as finickity with grubbing up.

Love the way this stuff happens right before im going away or whatever and need the car, ol\' murphys a f*ck. Any ideas would be lovely.

[boon]

You\'re not running an AFM any more are you?

[Guest]

No sir stock V7 map sensor on TB.

[tebbyj]

Check you O2/AFR sensor outputs, had similar issues on a GTB ended up being a bung O2 sensor. was stuck at .3v then every now and then would jump causing massive hesitation, almost verging on bunny hoping.

[Guest]

O2 is a AEM WB. Seems fine with out checking it with another but nothings changed as far as readings etc. No difference with it disabled either.

[lachlan]

sounds like some data logging would be mighty handy

check fuel pressure ? not the line/sock/tank sucking shut randomly

what is the connection from coil to plug like ? the rubber boots etc

[boon]

Yeah considering you have a G4, go for a drive logging eeeeeverything, see what goes crazy when it cuts.

[Guest]

Everything is in wack nothing funny in values and fuel pressure was one of the first checked.

The V9 sti coils are brand new like under 1,000km.

Just swapped on a non turbo v5/6 style pack with the plug on side rather than lead. Ran mint for a 10 min drive thro entire temp and load spectrum. Will swap in the COP again when its cold enough and see how that goes.

[Guest]

Sorted.

The coils had push on terminals instead of OEM connectors which were sealed into the plug with some varnish looking shit. Anyway the earth wire was broken right back where it goes into the sealant shit. Anyway after 20min of flicking the shit out with a pick I soldered in a stock COP connector and no more issues.

Strange how it sounded so different to dropping a lead completely. My first thought was coil as was mates but dismissed that one due to new parts and the way it acted. All fixed anyway no harm done. :-\