As above, the car is a widetrack blob STI with PPP and I'm getting either fuel cut or boost cut (how to tell the difference?) on full throttle. Car is standard apart from a Blitz Nur Spec R. What do I need to look for? How can i fix it?! It's getting me down!

 

im guessing u have a decat down pipe which is causing boost creep. U can adjust your actuator arm to stop it. Boost gauge? If not then fit one before u touch it

 

I've only had it a week! Got temporary insurance for Easter till my policy changes over next month. Car has the PPP and the Nur Spec R. That's all I know. I'm pretty sure it's only got the cat in the downpipe now. But I could be talking rubbish. Gutted about it! I was hoping it was the MAF or a coilpack breaking down but its looking pretty clear it's not going to be that.

 

does it happen in all gears

 

2nd 3rd and 4th so far. Not had chance to try 1st or 5th

 

its unusual to fuel cut in 1st and 2nd. Is the engine management light on

 

Nope no lights at all. Might not be 2nd, only driven it today!
Actually I'm guessing at overboost. At say 3/4 throttle it's almost like the power 'pulsates', and at wide open throttle it's jerky and juddering. Might be plugs or boost solenoid wants cleaning. I'll have a try at cleaning it.

 

hi mate, could possibly be your plugs, mine had this problem, stuttering etc, changed maf etc. new set of plugs sorted it. well worth a look..

 

Thanks buddy! Will try cleaning the boost solenoid then change plugs! NGKs?

 

u would know if it was overboost because a fuel cut is pretty violent, the boost solenoid would cause it if it were stuck open but it would put the light on, if the valve were stuck closed u wud be at wastegate spring pressure (half boost). I think maybe plugs or it might have a decat downpipe and not been mapped for it

 

yes mate, ngk pfr7b are the ones

 

From what I'm reading it seems to be plugs. I would say its a severe jerking under WOT at higher but defo not violent. And no engine lights either (checked the bulb is still in too!). Looks to be plugs!

 

Driven the car quite a bit today (but about 150miles). Car seems to have stopped all but the slightest of pulsating on its own. Am I just subconsciously driving around it?

 

Also seems a little down in power in 3rd, or am I just getting used to it?

 

Drove it 110 miles home last night, all is fine! Shes a fickle mistress!

 

*UPDATE*

Fixed by Brian at Cams. Turned out to be the NGK plugs that were fitted in January by a well known Subaru garage were actually Bosch, not gapped at all (2mm?) and only finger tight. I wont name the garage but will send by PM if interested. Car is now running like an absolute beast. My license wont last long!

I thought I'd post an update as I saw plenty of threads that looked to be never resolved when I was searching.