I filled up again today and I got 13 MPG. This is after getting 15 mpg on the freeway last week.

here is a post I made about the low freeway mileage last week.

The question is could the drop in mileage be due to the new K&N air filter I put in 2 weeks ago?

I also dropped in 4 Boshe Single Platinum plugs. I only put in 4 because I can reach the other 2. Could this be causing the drop in mileage?

 

did you gap the plugs?

 

The filter will not cause your mileage to drop. You need to check your plugs and make sure they are gaped right, along with your wires. Make sure your MAF is clean and your vaccum hoses are hooked up right from the install of the filter.

 

i gapped my plugs to .054 because thats what i thought the guy at the auto parts store said. When I replaced my plugs I had to remove the wheel well and there were 2 hoses connected to a ball. Does this have something to do with the vacuums? I did hiss when I removed the hoses. I did plug them both back in.

 

Neither one of those things will KILL your milage unless something is bad wrong.

Do you have a check engine light?

Rich

 

your first problem is with the brand of plugs you installed......your second problem is you NEVER replace just one plug (i had a dead plug in my truck and i replaced them ALL).........and if you didn't gap the plugs to the right gap, you could lose milage fast...

the K&N is NOT the problem....

 

Replace ALL the plugs with Motorcraft platinums, and plug wires. Replace the K&N filter with an OEM paper filter. And last, clean your MAF sensor........

 

LOL.. you'd think the world will stop spinning if you use a K&N filter and did'nt use anything but motorcraft plugs.

For an honest milage figure you really need a average of three fill ups. Or more would be even better.

btw, change those other two plugs.

Rich

 

+1...always change ALL the plugs. Get to those last ones, and be persistent. Are the wires fully contacted?

 

Not to turn this into a spark plug war but the Bosch plugs can be the problem and since you only changed 4 of them that is making it worse. The K&N will not cause the drop in mileage but a bad gap or bad plugs will. I've always used Autolite dp plugs. The Bosch made my truck run like crap. But if you always use the Bosch plugs and have no problems just change the other 2 like everyone suggested.

 

This is the first time I have used Bosch plugs. I will get around to changing the last 2 sometime next week. Those 2 are pretty hard to get to and i need to figure out how to get to them.

I dont have a check engine light on.

Could the Bosch kplugs be the reason my milage has dropped?