a4 1.8t problem

[ger83]

hi all, i have an a4 1.8t ''04'' and start loosing power during boost there last friday, ive since had it in for a diagnostics today since my vag com cable just got order there today and should have it in the next two weeks, anyway he did a full read of the car and it showed mis fire cylinder 1 and 2 so he deletd the fault codes and checked the voltage reading for the cylinders, cylinder 1 and 2 were going up to 1.25 and jumping around a bit while 3 and 4 were stable so he replaced coil 1 and the spark plug and check it again and it made no difference atall he said it could be a build up of sludge so suggested a good engine cleaning product to be added to a full tank of petrol to see if it makes a difference, ive since had the check engine light flashing again when excellerating over 3000 revs whilst the car splutters and shakes its a nightmare so though id post up to see if any of you guys have experinced this or have any idea what it could be.

[randall977]

Yes, I have had this problem - it was a coil. I replaced the remaining two which had not been replaced as I believe when one goes it generally triggers the others or weakens them...

[ger83]

the two coils which i replaced were orignal vwag ones but the new ones were bremi which i bought from otto so maybe il pay audi a visit and get orignal ones and see if that sorts it

[randall977]

Hmmm, wouldn't have thought the new ones you put in would be dodgy - sorry I thought you had only replaced one of them. I did use genuine parts...of eBay. Part revison R coils are the ones you want.

[RickT]

Check all the coils and re-read the fault codes for the misfire cylinder..

ALso check any hoses around the back of the block, its common for a vacuum hose on the back of the block to leak which also causes a misfire.

Where abouts are you?

Cheers

Rick

[ger83]

im in dublin, i checked all the hoses and lisend for blowing,i also cleaned and tested the maf and cleaned the throttle body out and the injecters aswel as fitted new air filter, maybe the bremi coils i got arnt the best and are causing the missfire im not sure because apparently there was a bad batch of ignition coils in circulation, so il try audi for two replacements and see how it goes, cant hurt to chance it