Stuttering on Wide Open Throttle

[Mole]

Hello,
I've been chasing a fault on my VR4 for the past few days, so far I've checked the coils and changed the plugs.
The car is totally standard except for a free flowing exhaust and decat.

http://www.youtube.com/watch?v=-yhXkfObhTg

In the video around the 5 second mark, I'm guessing that is fuel cut? But the stuttering at around 45 seconds which causes me to back off the throttle isn't nice at all. This only happens when the throttle is wide open.

I don't have a boost gauge installed but I am planning on doing so.

Any ideas as its very annoying, and worrying that it isn't running 100%

Thanks

[fassi1]

Does it happen at any speeds? You shouldn't be hitting fuel cut with stock boost.

[Mole]

Seems to be in 3rd when it really comes in, If I was to put my foot down from standstill, it won't do it until it gets into the higher gears. Although that first jolt in the video it literally cuts out, then comes back in after dropping from 5500rpm to 5000rpm.

I'll get the boost gauge fitted asap so I can actually see what its boosting to.

Edit... I've just had a thought, I'm wondering if its fuel starvation, I'm going to fill the tank up tomorrow and see if it does it, I need to do the fuel filter anyway as I'm unsure of when it was last done.

[Nick Mann]

It could well be fuel cut, although it is happening a little higher up the rev range than I would expect. Maybe that is just because you are hitting the gear at nearly 5000rpm anyway. Cold outside temperature always tips you over the edge if the car is boosting to close to the fuel cut limit.

I'd certainly get a boost gauge on there, I'd also be checking the boost & vacuum pipework for leaks.

[MarkSanne]

Do that fuel filter check / change. Always good to day to have it done and be sure that's not restricting. As it so happens the bloke who bought my VR4 engine from the crashed Legnum last year had serious hesitation problems all of a sudden. Much worse that this stutter here. Turned out a very dirty, blocking fuel filter... I wouldn't have put much money on it, but it was a good start (after checking and fixing air leaks :)).

Tonight I'll see that filter myself, I'll make pictures :)

[Z-Kev]

Have you pulled any codes, check all hoses and the air filter , also think of hoses collapsing and blocking airflow as well, not sure thats fuel cut as it seems quite polite compared to my fuel cut

[MarkSanne]

Here's that dirty filter.
66116

[Mole]

I plugged in an old vagcom cable a few weeks back, only old codes were oxygen sensor, which cleared, but I haven't checked since, I'm fitting a wideband kit at some point in the next week so if the oxygen sensor is at fault, that'll be fixed anyway.

I remember when I bought the car, the owner said the previous owner to him had put it away in storage for a few years, so I'm thinking that perhaps stagnant fuel in an old filter has caused it to deteriorate, plus it probably is as old as the car!

Mark, that fuel filter looks like it wants to escape through the pipe!

[Davezj]

only rely on the codes that are flashed on the dash board i have never found the eror code to be reliable when read with evoscan.
flashy dash always.

[Gly]

when was the last time plugs were done/checked?

[Mole]

Plugs were done over the weekend as I thought it was the plugs at fault, it had Denso IK20's in there, I changed them to NGK BKR7EIX's with the correct gap.
I used some electrical contact cleaner to clean up the coils and HT leads, but the stutter is still there.

I shall be pulling the codes when I next get a chance

[WillVR4]

When I was doing research on the car I bought I found a thread of a previous owner having a very similar issue/symptoms to this. It turned out to be one of the coilpacks arcing to the engine.