Mine is a 5 speed as well...

 

I got 13 before my complete tuneup now I'm getting a solid 17.9. This with an aggressive right foot

 

I'm taking it to a friends friends shop to have the codes checked. Could I use a obd II( or whatever it is) checker for those codes or do I need something else?

 

What did this "complete tune up" entail?

 

Oh F1, he has a 2000 . No cap, rotor or wires.

For your 2000, fresh fluids (oil, tranny, diffs, tcase and coolant), filters (oil and air) and plugs. Also, run some Seafoam through the intake and gas tank.

 

For your 2000, fresh fluids (oil, tranny, diffs, tcase and coolant), filters (oil and air) and plugs. Also, run some Seafoam through the intake and gas tank.[/QUOTE]

Oil(and filter) done, plugs done. put an aem intake on with brand new filter. Tranny fluid looks and smells bran new, shop said diff fluid is good, haven't checked tcase, coolants full but you mean like a flush and refill right?. Seafoams next on the list for me to do. U say do the intake? It comes in an airosol? Do I remove the filter and spritz into the tube or is spraying the filter good enough?

 

Cruise and 55 yields 23-25!
Plugs and some injector cleaner (STP complete) improve things from when I bought my 01 but in the city it isn't great but cruise and 55 ...

 

Stupid coil packs get me EVERY time! I think it was the 1987 in Mr. Anderson's alias that tripped me up... or I'm old. Maybe both. Or neither. I forget. Squirrel.

 

Oil(and filter) done, plugs done. put an aem intake on with brand new filter. Tranny fluid looks and smells bran new, shop said diff fluid is good, haven't checked tcase, coolants full but you mean like a flush and refill right?. Seafoams next on the list for me to do. U say do the intake? It comes in an airosol? Do I remove the filter and spritz into the tube or is spraying the filter good enough?[/QUOTE]

You add it in through a vacuum line. I used the brake booster line. Search YouTube or "the google" on how to do it. It's a piece of cake. Good luck! Oh, and change your plugs afterward...

 

You add it in through a vacuum line. I used the brake booster line. Search YouTube or "the google" on how to do it. It's a piece of cake. Good luck! Oh, and change your plugs afterward...[/QUOTE]

Change my plugs? They are brand new!!!

 

 

You won't need to change your plugs after.

But yes, pour the Seafoam slowly through the brake booster line into the intake with the car running (about 1/2 of a can). Shut it off, wait for 5 minutes and enjoy the smokescreen. Dump the other half of the can into the gas tank

 

If you do a full tune-up and it doesnt fix it there maybe something bigger wrong like a clogged cat.

 

Just as a follow up - assuming you've gone through the basic tune up steps, I was getting poor MPG and no trouble codes. It ended being the O2 sensor for me. It jumped from 8-10mpg to 13 mpg on a tank that's 3/4 full. I'm expecting it to go higher on my next full tank with the new O2 sensor. If O2 sensor has 100k+ miles on it might be worth trying.

I picked up my O2 sensor from
You likely have 2 O2 sensors. If you replace it, make sure it's the upstream one before the cat.

 

One more thing you should check that I forgot to mention is your exhaust manifold for cracks. If it has a nice crack, that'll rob you of a few MPGs. And I agree with the above, that you should replace your upstream o2