Golf VR6 misfire/hesitation and loss of power

[NickM91]

G'day,

Something of an ongoing problem i've had. My VR6 will hesitate/misfire and lose power, sometimes quite violently at exactly 2850-3000rpm, it does it regardless of gear but it is more prominant in the lower gears, and probably 40-50% of the time i go through that rev range.

It annoying the hell out of me, because it will literally feel like i've totally backed off the accelerator for a second, and you can imagine in first gear that'd feel quite violent.

I have had fuel pump issues in the past however since going through 3 of them, before someone finally thought to figure out why. They found out that it was caused by a build up of sediment in the tank from s**t fuel clogging the pump and burning them out. Could this issue still be a cause, could it be fuel pressure issues, injector issues or is it likely something else?

It will pick up again after that, however sometimes it just feels gutless. Comparable to my mates GL! Others its fine.

Coil pack plugs and leads were replaced a few months ago with new parts so there shouldn't be any issues there.

I do have a small vacuum leak in a little pipe at the back of the engine which i haven't gotten around to fixing, however it had the same issue prior to that opening up anyway.

Any help would be great,

Nick

[NickM91]

Reading back over what i've written i think i'm over exaggerating the issue a bit, but none the less it is there. Any Ideas?

[G_1991]

Check ur coilpacks, i had the same problem but worse and it ended up that i wad only running on 4 cylinders for a day or so. Take it to a guy that does vw's, parts about 330-350.

[G_1991]

Check ur MAF and sensor that could be causing you a few issues

[VR28LT]

Mate i cant exactly tell you what is wrong with your car but my VR had a vacuum leak and was doing the same thing you reported while under light/medium load going up hills . Now that the leak has been sorted all of the hesitation and misfire is gone

[pimpossible]

Can I ask which pipe was leaking cause I'm having the same problem and I don't think it's my MAF.

[dc10]

when the fuel pumps were changed, was the tank checked?.... i doubt that youve managed to fill up with dirty fuel enough in between each fuel pump to kill the next one... so if the reason each pump died was actually sediment build up i would check to see if whoever changed them each time actually had a look in the tank while pump was out to make sure there is not a whole load of existing crap in there from years of build up... might be an idea to empty it and clean it out. then change the filter... you should also try changing the coolant temp sensor as well, i think that has something to do with controlling the amount of fuel thats fed through... not hundred percent though. also check fuel pump relay if you havent already. go for a quick spin with the MAF unplugged see if theres any difference.. and next time you fill up try one of those fuel system additives that cleans the injectors etc.... hope something here helps, ive just had a very similiar prob with my vr, but it turned out to be a combination of leads and coolant sensor causing wack temps/misfires/stumbles

[VR28LT]

Can I ask which pipe was leaking cause I'm having the same problem and I don't think it's my MAF.

http://www.vaglinks.com/Docs/VW/MKIII/ETKA_VW_VR6_EGR_PartNumbers.pdf

pipe number 3 on the link of the VR6 vacuum system / EGR

[NickM91]

Looking at that schematic pipe '3' is also the one with the split on mine. Although my vacuum system looks slightly different. It is the pipe that connects to the throttle body/just near it though

I've been having trouble sourcing a replacement pipe, can anyone else help?

When i get a chance I'll have a go disconnecting the MAF and see how it goes.

The coil and leads should be fine as they were replaced a few months ago.

After the pump died the second time i finally took it to someone with enough thought to check why it happened and he drained out the tank and said he couldn't believe the black slurry that came out the bottom. So hopefully that shouldn't be an issue anymore, however i did replace the fuel filter before he did that so it couldn't hurt replacing it again.

I'm very keen to resolve these issues as i'm looking to sell the car shortly as I will no longer need it as of March due to a new job.

Cheers

Nick

[Golf Loon]

Fix the vacuum leak.
You can use an expensive VW bit of plastic with a baffle. Or a cheap piece of rubber hose.
Fix that and the car will go heaps better.