Slight Hesitation When Cold

[seefive]

Hi

 

2008 mk 2 petrol auto exclusive(not HPI)

 

has developed a hesitation when pulling away cold. Pressing accelerator harder than normal clears it, and it then drives OK.

Recently serviced (Indie garage I've been using for years), 18k miles on the clock. It feels like the speed limiter is holding it back. Limiter is switched off, and doesn't operate below 18 mph anyway.

 

The car was a cat d write-off, repaired before I bought it a year ago (with my knowledge), so no warranty. Hope this isn't something nasty developing.

 

I've tried changing petrol brand, and using manual side of the gearbox without any improvement. Hesitation happens in forward and reverse gears.

 

Any ideas welcome

Thanks

[sifaan]

I have similar symptoms (as well as few others) and in my case the fuel pump is packing up... could be the cause of your problems as well

[Randombloke]

Two easy things to check first:

 

Throttle position pot - it might have an area that is worn. If you accelerate on the throttle and it happens but doesn't on cruise control, this is fairly surely the problem.

 

Air mass flow sensor - could be dirty or need replacement. Do not touch the element - squirt with carb cleaner and blow dry with compressed air.

 

Feedback please.....

[seefive]

Two easy things to check first:

 

Throttle position pot - it might have an area that is worn. If you accelerate on the throttle and it happens but doesn't on cruise control, this is fairly surely the problem.

 

Air mass flow sensor - could be dirty or need replacement. Do not touch the element - squirt with carb cleaner and blow dry with compressed air.

 

Feedback please.....

 

Changed the spark plugs today (surprisingly easy for a non-mechanical type like me) and that seems to have fixed it. Noticeably sharper acceleration and keener to change down (auto box)

 

Plugs are scheduled to be changed every 40,000 miles which I think is too long. They looked dirty and worn, but nothing nasty like oil or burnt electrodes.

 

On a car with such low miles (18k) I wouldn't expect any major wear. I was more concerned about possible engine management or auto box software-related issues