Mercury Sable Station Wagon High Idle and Poor Gas Mileage

Reader Question Greetings Austin

I have a 1996 mercury sable wagon V6 with just over 200 000 km on it it’s still running good and I try to take care of it. lately the rpms have been running really high and affecting my gas mileage. about 6 months ago before a road trip I replaced all the spark plugs and wires changed the oil and such and everything was beautiful I was getting over 600km a tank. but lately it’s been acting up.

I took it in for an oil change and got them to use the high mileage oil and flush the oiltank (if that makes since) and I’ve since driven it about 2000km and noticed the rpms going crazy so I took it in and got the oil changed again to regular oil and asked if there was anything wrong with the oil and was told it was fine just really dirty. but the rpms remain the same.

Now I only mention the oil because I know in my car if I forget to change the oil after the regular 5000km I notice the rpms start going a little out of wack. maybe it’s something else? I’m not sure hopefully you can help

THANKS

Jess

Well Howdy Jess,

There are two items that come to mind that I would look at first.

1. Idle speed control motor – sometimes they get dirty with carbon inside and can be taken apart and cleaned, and sometimes you just have to replace it…its actually pretty cheap at the dealership and you can replace it yourself.

2. A vacuum leak under the hood – open the hood with the engine running and look and LISTEN for a hissing noise. Sometimes rubber vacuum hoses will break or get unplugged and will cause a vacuum leak, which will cause the engine to run bad or increase the idle speed like you mentioned.

Keep me posted as to what you find out.

Blessings,

Austin Davis