A couple weeks back I took the 04 to my tech who did a routine oil change and replaced my spark plugs. Old plugs were Denso iridiums had about 35k on them and replaced them with same. I am suddenly finding I am getting about 40 miles less per tank....burning 1/2 tank at less than 100 miles when it used to be 120-130 normal driving. I just now reset the NVRAM in hopes that will help. Any other thoughts?

Car otherwise seems to run just as well if not better than before.

 

I was going to suggest reset NVRAM. Should help.
But, you may also want to check to make sure that all connections are fit correctly. Try cleaning air filter/ maf sensor.
Also, how is your cat? Clogged/ damaged will cause bad fuel mileage

 

i'm having the same problem. what is the NVRAM you speak of?

 

put the car in the on position , pump the brake 20times in 8 seconds and watch your oil gauge move, if that happens then its reset

 

Will give it a couple days after restting the NVRAM and will check the connections tomorrow. Air filter was cleaned last summer...can't really look at it til the weekend. Not sure about the cat, it has about 35k on it.

 

If this happened concurrent with the new spark plugs, I wonder if they are installed correctly....

 

You mean as in leading in trailing spot and vice versa? I would HOPE not but short of going in again and having it looked at....which I suppose I just may have to do.

 

Ok so went to my tech this morning and mentioned things to him. He is almost certain he didn't pay attention to the fact that there are trailing and leading plugs......

UGH.

 

From what I read on here if you had the plugs swapped around there would be more issues than just a slight loss of gas mileage.

These are reasons to be doing your own maintenance though. :P

 

When you live in an apartment complex with no car repairs allowed in the driveway and a car like this, you go to a mechanic. He did it right before.....this time he just messed up and forgot.

 

Perhaps one of the spark plug wires didn't get seated fully. You need to push them on pretty hard until you feel them click.

 

I know you probably would not do this, but you and a buddy could always take it to some random parking lot and do maintenance. Where I used to live there was a Target that was closed down and the parking lot was free and clear, and also right next to a auto parts store in case something went wrong lol.