leaking flexi on the downpipe could this be the problem

hey guys just found out that my downpipe has a leak in it,

at the bottom of the flexi,

and my car feels like the boost go up and down up and down when i give it full throttle just for a little while now before it was even worse, then it acts normal again until  the next time i start the car after it has stood for a while and got cold my guess is that when the downpipe gets extremely hot and increases in size maybe the leak stops ?

the car also drinks alot of gas even if driven  very economical

we can take this from the beginning i bought my vrs 2002 early this summer it had a civinco piggyback box so about 225hp 338nm

and it ran fine only thing i noticed was that the tachometer was a little unstable and when the car was started the first start in the morning it could stutter but only on idle when cold

and when the car was driven it ran perfect no issues at all, on all of the day even if it stood still a long time  it only had the issue the first start up of the day

and i called a skoda workshop here in sweden and they told me to come there and change my coils on the warranty so i thought perfect free coils and booked a time to come in

however after they changed 3 out of 4 coils 

the car now misfired all the time both hot and cold on low revs between 1000-1500 rpm

every redlight, every crossing everytime you slowed down and was in the 1000-1500 rpm range it misfired 

so i went back and told them about this and eventualy they took the car in again and connected a computer to it while the ignition was on and found no fault codes so the mechanic said change the spark plugs we cant see if they are bad on the computer

so i  put in new ngk pfr6q but it was no diffrence still misfired in low revs

so had to call them again and book a new time to come back

this time another mechanic came out and connected the data to the  car whilst i was driving, at first it was just showing a misfire on cyl 2, and as i drove stoped and drove there was a harder misfire and it showed misfire on 2,3 and,4th cylinder

so he said we must take it in and check this out properly,

so this time they checked the coils and swaped them around but the misfire still were there all the time on cylinder 2 

so they compression tested the engine and it was all good no problem there , after that they tested the injectors and no problems there either

they changed a crankcase hose that was broke but that did not make any diffrence it stil misfired on low revs

so now the mechanic uninstalled my civinco piggyback box and said now the car works fine its original now but it dont misfire anymore so it must have been something wrong with your civinco box

i thought  okej sucks to drive original but if thats the case its good to  finaly have the car back in good working condition 

so we went  to pick the car up  and drove away and the misfires had actualy stoped, but after a while of testdriving  we noticed another problem  now the car had a problem when it was driven full throttle

when the boost came  it felt like boost no boost ,boost no boost like that back and forth

so i tested to disconnect the n75 and the car ran better but was now very slow compared to before, so i guess it got no boost or very little boost, so called the skoda workshop and told them about this issue so took it there again and waited for some weeks until they contacted us again 

this time it had popped up a fault code that said low boost  and  it was because i had disconnected the n75 valve 

so now they tested the n75 with computer and it worked like it should and they also tested the maf and it worked good aswell

and the cables to maf and cables to mapsensor no faults there either

and the cables that were wired from the civinco box to and no faults there

 they couldnt find anything else then the code that said low boost so now they told me that they wont do anything more on the car and that it wasnt their fault that the car was going like this

and that the change of coils never could cause this 

so when i got there to pick it up again  i asked the mechanic if he couldnt take away the code  to see if it popped back up again now when  the n75 was connected but they didnt want to do that 

now they wanted to pull down my turbo to check it and the cost of doing that  was more then  buying a new turbo  so we just took it home  instead

and when i got home  i started to look at the car, and when i felt with my hand around the wastegate actuator  to see if it leaked there and it didnt

the car was on idle and  i heard a leak from the downpipe it was hadly noticeble but i felt with my hand and at the bottom of the flexi it came exhausts on my hand 

could it has been this fault all along that caused misfires with the civinco box connected on low revs,  my thought is that maybe it got better ignition with the new coils and maybe the civinco box is more sensitve for exhaust leaks 

and now with the civinco box disconnected has problems when it  gets boost 

with the civinco box connected it never had any boost issues only the misfiring on low revs

and the boost is about 1,25bar with it connected  so if the turbo was bad  i would think that it wouldnt go so nice and fast with no issues whatsoever with the turbo with it connected

Edited 17 September, 201510 yr by rsdanne