Searched And Confused!

[kane_tools]

Seeking wisdom.

Hi all,

Well I have a random issue and it's got me fcuked.

Making it worse is searching and scouring these forums and it could literally be anything and doing my head in over it,

so I thought lets toss it on the floor for ideas.

The issue is on a freeway overtaking in second(and third) it will accelerate cleanly until it passes 4000 rpm ( then anywhere randomly between 4000rpm and cutout) it literally hits a wall!! like hitting the fuel cut early, not always but most of the time. Lift the pedal it will shift up and go normal again nor does it seem to go doughy or idle roughly after an episode.

It will ALWAYS accelerate correctly in first gear to redline every time and into second and makes the dash to 100k in normal time, pulls normally on the road up hills etc etc. When I say random on any given day it may not do it at all or once only, other days it will do it every time. Ambient temp is irrelevant as is operating temp or how long it's been running or fuel level in tank.

About the car-

it is stock, fuel is always 98 from one supplier..at first I suspected dud fuel but have put almost two tanks through it.

Fuel economy is still 'normal' for a XR6T (Up to around 14-15L/100 around town)

Idle quality is good, no vacuum, boost, or exhaust leaks.

Recently had 90K service by me, this included genuine filters, new iridiums (gapped to 0., 6x new genuine coils (one was cracked and it was missing like a basterd), new coolant/fluids etc, manifolds torqued, throttle body clean, boost solenoid lube. It went like it was meant to, till this crap problem about a week ago.

Things that seem a bit odd-

it smells farken rich at idle with a very random and very slight miss, although this has not really changed from when it runs well. It seems quite loud for a standard exhaust but again no different from when it ran properly consistently.

The wiring to the rear exhaust side cam sensor seems a little crispy from heat exposure.

On two occasions if you immediately pull it up after a splutter you can tell half the cylinders are cut out or on trailing throttle after a splutter on the road, through the exhaust you can again hear it running on half the cylinders then like flicking a switch it's back on all six after a couple of seconds.

PCM has been reset.

ETC has been reset.

I'm going to take it to CV to run it up on the dyno for diagnosis, but until then I'm baffled...is it new dud coils or wastegate issues or melted cat or weak fuel pump or valve float????

You guys decide!!!

Edited 08/02/10 01:29 PM by kane_tools

[400KwXr6t]

STupid question but its not traction control activating is it??

[kane_tools]

traction tried on and off.

this cut out feels similar to traction or fuel cut activating but feels more like putting a cork in the exhaust or intake, no noise or popping just BLAHHHH there is no switching.

Edited 08/02/10 01:40 PM by kane_tools

[400KwXr6t]

tricky, you just gotta check the silly things we all forget. good luck with it though, hopefully it is something simple.

[MRDOSE]

I had a similar problem mate, at higher revs mine would drop out and as soon as I lifted my pedal and boost of again its fine. CV replaced my coils and it ran like a dream. I hope it gets sorted for you

[linmup]

check the boost solinoid hoses incase one has come off the turbo or equator?? I once had a similar problem put it on the dyno and was fixed 5 min later.

[kane_tools]

checked ok, no leaks.

Would it go at all without exhaust cam position sensor or wild readings from this sensor? I just had another look at the wire harness and the outer layer sheath protecting the 2 inner wires just crumbles!! The 2 wires themselves are quite hard and appear brittle.

Edited 08/02/10 02:07 PM by kane_tools

[seduced]

Test the wires, it could also be your boost actiling causing overboostoverboost.

stupid text editor is playing up, I cant see what I have typed until its posted..... I meant actuator failing causing voerboost.

Edited 08/02/10 11:07 PM by seduced

[kane_tools]

Finally an end to this story!

Got it put on the CV dyno yesterday and the question of which plugs/coils were in the car after it done it's dying trick.

So I said almost smugly new ford coils and NGK iridiums which were also fairly fresh....Con then said they just don't work in our cars..who am I to doubt him.

He said the cross matching part from NGK or any other brand will give probs such as I had, he swears only by the GENUINE FORD DENSO plugs.

Still sceptical I grabbed a set off Con, got the boys to gap them down from 1.1 mm.

Needed to go to work with car so I fitted them when I got home and WHOA what a difference and problem fixed.

I only wish I had time to fit them there and then and run it up again, they were flat out, I had to run.

It is stock and pulled 186.2 rwkw with the farked plugs all other things being sound such as AFR's and boost etc, I wish I knew the after reading with the new plugs because they really woke it up.

So case closed and another happy CV perfomance camper!!

[arjey]

tricky, you just gotta check the silly things we all forget. good luck with it though, hopefully it is something simple.

make sure its not in park