help needed... missfiring at 4-4500rpm. feels under powered

[vr4cobra]

Hey guys, last weekend with the help of Christian I replaced my tappit cover gaskets, ignition leads and fuel rail seals... I also tightened my front pipes up as they were leaking.
Even since we did the seals and gaskets ive been having some issues under boost. It backfires at about 4-4500rpm under WOT and can be heared and felt pretty clearly in the car. Feels like a flat spot.
I can also smell very strong fuel under any boost, but on idle it doesnt smell fuelly and under WOT above 4500rpm the fuel smell goes away again till revs drop again and feels underpowered all thro the rev range. Under light throttle and letting the boost spool up it smells very fuelly but also the car feels like it pulls very hard almost like WOT...

I havnt had much time to scope it out yet but I had a quick look and couldnt see any fuel leak or smell anything untill I reved it at throttle body then I could smell alot of fuel but still no visual leaks...

Anyone have any ideas wat the issue could be?? I have already done an ecu reset which stopped the flatspot and backfire for only a few days but car still felt really underpowered still and very fuelly smell was still present...

 

[Stanislav]

stuffed coil maybe?

 

[vr4cobra]

Hope not but it wasnt doing any of that before working on it and started straight away afterwards

 

[VOLK]

Any codes?

 

[vr4cobra]

Havnt had a chance to run them yetyet will try on the weekend

 

[naughtika]

coils have stuffed up your plugs..


does it feel and sound like a subaru after WOT?

 

[vr4cobra]

Nope sounds normal except during missfire and drives smoothly under light throttle. front plugs were fine, I forgot to check the rear ones while had a chance, they are vk22's with about 10-15k in car...

 

[vr4cobra]

Anyone else no wat else I should check on the weekend? I will be trying to scope it out on the weekend

 

[TME_Steve]

Plugs, leads, packs.... Something got moved and broke I reckon, so leads is my bet

 

[vr4cobra]

Ok so today I had a lil time to scope out the issues...

First I looked for leaks... Nuda
Then sprayed some stuff on could to look for arcing... Nuda
Then checked all vacume hoses to ensure they were attached properly... All good
Checked the vacume to FPR incase internal leakage... Still nuda
loosened fuel loop and front fuel rail and re tightened rail the loop...
Noticed my front rocker cover breather had a bit of oil residue around it which wasnt.there before so I cleaned it off and put a small hose clamp.on it ...
While I was at it I checked all intercooler pipes nice tight no leaks....

Ran out of time to.check.anything else today but when.i left my workshop car ran sweet... No missfire, pulled hard the whole way I thought sweet must have done something right... But after idling away loading the kids in the car it started smoking white blueish smoke out the exhaust which I need my garage stem seals done, but when leaving my place it started to.missfire same place again and having flat spots power again. But later on I gave it a lil pep and ran nice and smooth again and plenty of power....

Thinking I better get my.valve stem seals done asap as it could be the cause of my issues maybe fouling up the plugs when the start leaking??

 

[chocco]

If its coming and going man I would be pointing to the coils.

Mine does it here and there too, sometimes its awesome and pulls 16 pound
for an hour or 3 days...Other times it breaks down at 4000...

Try another set of coils dude and you will be surprised the difference a new
set will make.

IMO - Get Christians COP kit and be done with it.

 

[vr4cobra]

Yeah I do want the COP but not enough $$$ to get it yet but hopefully before tune date, might have to try new coils for a bit and see how they gogo, cheers Christian

 

[chocco]

We got 3 - 4 months man heaps of time