Car vibrates badly on boost!

[dgogborne]

my ibiza cupra 1.8 20vt is getting on my tits! m.o.t 2 weeks ago failed! minor things, most major was lamda sensor. got it back on the road wednesday, thursday had to replace coil pack x2 and set of plugs. since doin that car drives amazingly... until... you want the turbo to go above 5psi! then it just vibrates like your on a harley and back fires when you take your foot off of the excelerator. i thought maybe a popped hose of something, but i can't find any thing. before i changed the coils it did this all the time now its only when you hit the power band?
any ideas?

 

[tommy2008cupra]

sounds like another coil mate tbh

 

[ibiza_adam]

I'm not overly clued up on the turbo lump mate! But what you describe does sound like a miss. If it's popping etc on over run as the revs come down then thats a load of un-burnt fuel igniting in the exhaust. Does it idle fine? If you blip the throttle at idle does it bog down?

 

[dgogborne]

no it idles fine. how do i check the last 2 coils, i took it to a garage last time and they charged me 150 quid for 2 coils and a set of plugs.

 

[tommy2008cupra]

do it urself for half that mate

 

[dgogborne]

are the coils the 4 little black boxes on top of the engine, if they are how do you take them off and how do you know if there nackered?

 

[tommy2008cupra]

yep they are remove the sh*t from top of engine with allen key then should just pop out mate, check the connection on the other side if its black then that is most probably the one that is failing is it throwing up eml?

 

[dgogborne]

no it hasn't yet but i haven't really taken it out for a drive. my splitter is like a snow plough in this weather, i've already snapped a couple of fixings! cool cheers for your help i'll have a look at those coils in a bit.

 

[tommy2008cupra]

ye no worries mate, i think it was one of my first posts to lol cost around £20 each from euro car parts etc