Fuel economy - notes and alternative(s).........2017 VW Jetta S (5M)

[ezshift5]

This website shows - over 40,000 miles of 65 City/35 Highway use - an average of 40.8 MPG.

That being said, the VW Owner's Manual says 40,000 is spark plug change time.

I think that is much too early.

I'm going to watch the MPG real close (to see if it goes down).

Also I'll monitor starting time (It's been quick to fire up since brand new)

Then I'll be real alert for any misfire during hard acceleration.

Comments?

Recommendations?

ez

[JockoT]

One issue that can occur by leaving the plugs in too long is difficulty in unscrewing them. You don't want to risk damaging a head for the price of a set of plugs.

[ezshift5]

Thanks for pointing this out JockoT.

IIRC - I believe the OEM plugs are treated with an anti-sieze process (I sure hope so).

Tks again,


ez sends

[luv2spd]

I heard that engines with direct injection wear out their spark plugs faster than normal fuel injected cars. I'm not sure if your Jetta's engine is direct injection. The interval for my 2006 Mercedes C55 is 90,000 miles to change the spark plugs, but it's a non-turbo fuel injected car; I had to change out 16 spark plugs and they all looked ok at 90,000 miles.

[Draigflag]

I'd stick to the service schedule, 40k seems a long interval these days for a modern engine. They recommend an annual change for mine, although my engine is high compression direct injection. At over $100 for a set of four, I asked the mechanic to do them every two years now. He showed me one after such an interval, I must have done less than 8k miles. It was pretty burnt out.