I finally got my 4agte back on the road yesterday after 3months in the garage, drove it around all day and it ran sweet, then took it out last night and gave it a hammering, all was good. Started it thismorning and drove to uni and it was ####ed, idles rough, but seemed to drive ok under 3000rpm. Anything above that and it would build a little bit of boost, but wouldn't accelerate and wouldn't rev, just make a growling sort of noise, if I held the pedal flat it would kinda surge along picking up fractionally every couple of seconds then dying in the arse again.

Also it does this weird thing when free revving it, if I back off and straight away hit it again, it makes a noise like sidedraught carbs sucking air (from the turbo) and takes a second or two before revs rise. I have attached a video of this, take note of what I'm doing with the throttle as it revs.

I initially pulled plug leads off one by one and identified a dud plug, pulled it out and sure enough it was fouled, I put plugs back in in the reverse order and it was the same plug not firing (ie not coil/lead problem). So I went and bought new plugs and put them in, same problem, except it idles slightly better.

compression is 160psi in all 4. It just seems strange to me that it suddenly started for no apparant reason. The only change was a squirt of octane booster thismorning, which has never caused a problem before...

http://www.youtube.com/watch?v=zpqFyimkzlg

ideas?

no air leaks in your turbo plumbing sucking?

u say it runs ok under 3ooorpm, a ign lead can seem fine except then break down under load on that fouled plug, but it shouldnt break down that much to fully foul up a plug. how old are the leads/plugs..

plugs are brand new, leads have probably done 30,000km. Can I test the leads without specialised equipment?

octane booster, do you usually run this additive? if not could be related, some change the burn pattern of the fuel to faster or slower burn properites slightly.

yep I've used it heaps (same brand) and never had a problem.

.

Sounds like a ECU/sensor issue
Check all sensor plugs
Try checking the earths on all the injectors
??

It sounds not entirely unlike an air flow metre or a fuel pressure issue. Although the plug swap and same missfire is a concern.

motor is MAP sensored if that changes AFM diagnosis?

I have most of the day off tomorrow so I'll start checking things, here's hoping its something simple like blocked fuel filter.

check the i/c pipes also suction on turbo and check for air leaks common stuff blocked filters and #### dont happen that often well never for me anyways