Fuel cut/miss fire?

[Gotpsi2008]

Hey all, so a few weeks ago I was driving home and came up to a passing lane, dropped to 4th and gave her full throttle. When I got on it as soon as I hit boost, the car jerked then continued pulling normal, fast forward two weeks, everything had been running fine since that day, just did the motor mounts, timing belt, Trans mount, and intercooler hoses (man did that suck), and everything went great til I was on my way home from the shop and the same thing, once in 3rd, once in 4th, jerked under high boost, mid rpm. I was thinking it felt like a quick misfire, but it didn't throw any cel, anyone have any suggestions? I'm probably going to order new packs and plugs regardless but figure id post this so if there is something else I'm missing here. Thanks!

[Gotpsi2008]

**update** took her out for a solid test run, during a full
Throttle pull from 1 up to 3, it gets a little backfire around 5500k in first, and backfired a few time during the second gear pull, the violent jerk seems to be more from a 2500k pull in 2nd or higher gears

[cpaugh]

I was noticing something similar. The only thing I could find was folks saying it was the high pressure fuel pump. I didn't believe that it could be that for me.
Fast forward a while... My timing belt broke because a mechanic left a torx screw behind the timing cover and it eventually found its way between the belt and the crank pulley.
So I end up having to pull the head. Among other things, I found that the cam follower was worn and the tips of the cam lobes were wearing away significantly. Apparently enough to cut down on peak fuel pressure and make the car miss.
That's the first place I'd look. Unless, of course, you've replaced it recently.

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[Gotpsi2008]

https://youtu.be/88EYoOJoVi8

Small clip of what it's doing

[Gotpsi2008]

I was noticing something similar. The only thing I could find was folks saying it was the high pressure fuel pump. I didn't believe that it could be that for me.
Fast forward a while... My timing belt broke because a mechanic left a torx screw behind the timing cover and it eventually found its way between the belt and the crank pulley.
So I end up having to pull the head. Among other things, I found that the cam follower was worn and the tips of the cam lobes were wearing away significantly. Apparently enough to cut down on peak fuel pressure and make the car miss.
That's the first place I'd look. Unless, of course, you've replaced it recently.

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I did my follower at 85k, I'm at 98ishk now, and it seems that after I shut the car off and turned it back on, I did a pull, no problems, then the second pull it started again

[vce1232000]

maybe a weak or failing in tank lpfp. Im just guessing at it thou. Mite want to get someone with a vag-com to runs some data logs and check fault codes

[cpaugh]

We're you able to inspect the lobes on the cam when you replaced the follower? If they were wearing, they could tear up a new follower. If not, then I'd say you dodged that bullet.
What is the status of your diverter valve?
Maybe some other guys with more experience with these engines will chime in soon.

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[cpaugh]

FYI... I really noticed the lobe tips worn when I saw the new cam. It became very clear then. Might be hard to see down the follower hole.

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[Gotpsi2008]

We're you able to inspect the lobes on the cam when you replaced the follower? If they were wearing, they could tear up a new follower. If not, then I'd say you dodged that bullet.
What is the status of your diverter valve?
Maybe some other guys with more experience with these engines will chime in soon.

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The follower I took out wasn't in that bad of shape but I can check it out tomorrow at work and check this one, and as far as the diverter valve, it's completely stock

[cpaugh]

New cam:

Old cam:


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[cpaugh]

My follower was replaced at 95k. I started cutting out under high load around 120k.

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[Gotpsi2008]

How do you post pics again?

[Gotpsi2008]

[IMG][/IMG]

[IMG][/IMG]



[IMG][/IMG]

- - - Updated - - -

Am I drunk or does that lobe look cracked??????

[cpaugh]

Seems less than optimal... Looks pitted. The follower is definitely better than mine.

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[cpaugh]

May wait for some other opinions. I don't want to get you spun out.

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[Gotpsi2008]

Already looking at cam prices haha, fml, I just did the timing belt yesterday too, but I guess if I do end up having a shit cam then I get to carbon clean the head and do the timing chain....but I am definitely going to pull the hpfp again tomorrow and inspect the cam a little better, it could have been the way the camera took the pic to make the lobe look cracked, I've never heard of a cracked lobe b4

[Zanny9060]

Coil ? that's what was happening to me turned out to be an ignition coil

[Gotpsi2008]

Coil ? that's what was happening to me turned out to be an ignition coil

Were you getting any cel?

[Gotpsi2008]

Thinking about it, this problem was pretty much non existent until I did the timing belt, mounts, turbo hoses, during which process the top of the engine got filthy and during the coolant bleeding process, got covered in some coolant, so I sprayed the top down with engine cleaner and rinsed it off, maybe this could have messed with the coil packs? It seems this only happens at 3/4-full throttle, I can ease into 1/2 throttle, hitting mild boost and hold it at that and it goes great, but as soon as I throttle into her a bit more the fuel cuts or misfire picks up

[BenMTL]

Your cam looks fine to me but your follower has uneven wear....Not usually a good sign.

Wear should be even, can mean the end of your HPFP is damaged?

[Gotpsi2008]

Your cam looks fine to me but your follower has uneven wear....Not usually a good sign.

Wear should be even, can mean the end of your HPFP is damaged?

I'm going to post pics in good lighting of everything today so y'all can take a peak, thanks for all the input so far everyone

[Gotpsi2008]

[swaggerwagon]

When was the last time you replaced your plugs? I was having misfires that weren't triggering a CEL (flashing or constant) so I ended up replacing my plugs. I couldn't remember the last time I did so I put in 4 new BKR7E and no misfire. $10 fix.

[klrider44]

When was the last time you replaced your plugs? I was having misfires that weren't triggering a CEL (flashing or constant) so I ended up replacing my plugs. I couldn't remember the last time I did so I put in 4 new BKR7E and no misfire. $10 fix.

^^^^^^ had the same issue. I don't know if the plugs were ever changed on my car. I put 4 new ones in and the fuel cut like feeling was gone.

[Luis_Heineken]

Having the same problem. P0192 is the code, replacing both pressure sensors this week end

[Gotpsi2008]

Haha well now I feel like a dumb ass...so I pulled my cool packs today, 1&2 were soaked, like a half inch of water in each hole, 3&4 both dry, the coil seals are dry rotted so when I rinsed the coolant off the top of the block, some water must have run down in, I dryer everything, applied dielectric grease, and runs fine now!

[cpaugh]

Haha well now I feel like a dumb ass...so I pulled my cool packs today, 1&2 were soaked, like a half inch of water in each hole, 3&4 both dry, the coil seals are dry rotted so when I rinsed the coolant off the top of the block, some water must have run down in, I dryer everything, applied dielectric grease, and runs fine now!

Glad you got some more input before diving into that cam replacement.

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