Mis-firing when cruising

[harpoonlouis]

I have a mis firing on Terrano II 2000 model.

When cruising at approx 60 70 miles per hour I get a progressive feeling that the motor is misfiring which increases if I gently accelerate.

If I switch off the overdrive to up the revs suddenly the motor picks up instantly and pulls away as it should. Same if I boot it hard.

The misfire is most evident at constant speed or very gentle acceleration.

It has only 52,ooo with full service history so I have no reason to suspect heavily clooged main filter but some of the issues seem a bit like the small filter problems folks have.

No leaks evident anywhere and motor pulls smoothly under all other conditions.

Any suggestions before I clean the micro filter?

Thanks

 

[rustic]

First of all welcome to the club, and your first post too.:thumbs

I assume you actually have a 2.7 Tdi
When you say switch off the overdrive?. I assume you mean change from 5 th gear down to fourth.

If it is the Tdi, then there are a few issues with the Maf, Mass air flow sensor.

Sometimes these just need a clean. special procedure required to save damaging it though.

The 2000 Tdi, don't always have the mini filter.

I'm sure someone with the Tdi model will be along shortly, as mine is the Td, ie non intercooler version, hence no MAF.

Best regards,

Rustic

 

[harpoonlouis]

Thanks for the quick reply Rustic.

Full description on log book is Terrano II SE Plus TD Auto Estate and it is an over drive switched from the auto transmission selector. It's the 2.7 Turbo TDi I believe since it is 2000 model.

Would have been a bit frustrated to have tunneled down under the power steering pump if it turns out not to have the extra filter!