Thread: Dumb question about LIM and MPH

Will a bad/leaking LIM have an effect on my fuel mileage? I have a bone stock(performance wise) 04 Comp G. I am currently averaging 16.4 MPG

A leaking lim will cause a vacuum leak possibly which will hurt gas mileage.

Ok that does seem logical. I was kind of hoping that is it. I will be replacing the gasket next weekend. I already put in a new air filter, fuel filter, cleaned the MAF, and TB about two weeks ago and it increased from 15.2 to 16.4 mpg but I think it should be a lot better than that.

When you do the lim change the spark plugs too.

I'm thinking about going with the NGK plugs and 8mm wires along with MSD coil packs.

No, no, no on the coil packs...

MSD sucks donkey ass.

Stock coils are way better.

/end of story

Stock replacement plugs are all you need.

And if you only drive city 16-19 mpgs is pretty normal.

I was told the MSD would create a better spark but not last as long. And all I do is city driving being from Chicago but I don't get on it too much. Just thought the mpg should be up there at least a little more.

Well, we are telling you msd coils suck, so dont use them lol.

MSD coils tend to fail prematurely.

I will take your word on the coil packs and go with the OEM. So for the spark plugs I should just go with the AC Delco? And also the wires?

Yup ac delco plugs and whatever set of wires you want, most stores have some sort of wires with a warranty.

I'd bet yoru issue is too much around town on 3.29 gears and enjoying the power. You aren't going to have a big enough vacuum leak to cause mpg issues

I see you live in Chicago. What is your typical driving? When I was there..even though I was on the highway..I was far from cruising at 70+ for extended periods of 20+ minutes. That is a killer for mileage, especially in a 3.29's car.

Thicker wires typically mean more insulation. That's what you usually gain with thicker wires.