Feels like the car is skipping a beat occasionally under boost.

[Twiggy]

Occasionally under full boost 4,5,6 gear the car kind of skips a beat, like its suddenly starved of fuel for less than half a second, it does it a few times in a row but then its back to normal again. The car is still pulling like a train while this is happening but just kinda drops a beat for 0.25 of a second.

It can't be clutch slip as i have an uprated Helix clutch and flywheel (fitted at the begging of the year) hold 355ftlbs.

I am running a stage one custom map by R-tech, with a great power and torque curve (no spikes of boost) (running 267bhp and 324ftlbs)

It only happens under full throttle.

When the car is on Vpower it does it less but work pay for my fuel and their account is with Total, best they have is  total excellium (97 ron)  and it gets this about 50% of the time, it happens more on Total excellium than on Shell Vpower, could it be something to do with the RON rating?

Is the fuel system maxed out?

Fuel pump issues?

Injector issues?

could diagnostics tell me anything?

other than this the car runs perfect.

Any comments or advice would be great.

 


 

[cageman86]

I had a similar problem with my car after having it mapped, swapped the spark plugs as I couldn't see anywhere in the service book where they had been done prior to me owning the vehicle, touch wood this hasn't happened again and it has been about 9 months since I done them, maybe worth a go...

[Twiggy]

I had a similar problem with my car after having it mapped, swapped the spark plugs as I couldn't see anywhere in the service book where they had been done prior to me owning the vehicle, touch wood this hasn't happened again and it has been about 9 months since I done them, maybe worth a go...

Will give it a go, thanks mate. 

[GrayMK5GTI]

I had this problem. I never sorted it, but after doing coil pack, plugs and fuel filter I think it was the LPFP as it was a lot worse when the car was low on fuel (less pressure forcing fuel through the pump)

Took it to Nick but it was behaving for him 

[john87]

I suffered intermittent 'coughs' on full boost in my GTI, turned out to be a combination of bad coil packs and fouled plugs.

[Twiggy]

Cheers guys, will get the plugs changed and see how it goes from there.

 

[bacillus]

Why has no one has mentioned doing some basic vcds logs to see if the problem is misfire, petrol starvation or none of the above if swapping plugs doesn't help??