Thread: Terrible MPG.. Any suggestions?

are you getting 13.3 according to the DIC?

My guess is tune up time and maybe o2 sensor time

If you are really getting 13 mpg that is awful. Be aware that changing your rims ( wheel OD) will change the DIC reading without properly adjusting the PCM.

That being said, here is a list of tune up items.

1) Front O2 sensor replacement
2) Spark plug replacement
3) MAF cleaning
4) Proper tire inflation (30psi bare minimum, I personally recommend about 34 psi when checking a warm tire)

If you address these areas without a change, the problem becomes a lot harder to find. Because then it could be any of a long list of insidious problems.

Good luck

^that and clean up your injectors too.

Im getting horrible mileage to, its down to like 11.6! I tried changing my plugs,maf,font o2 and its still bad. Are you running no cat? I dono if that could have anything to do with it because its after the front o2, but I finally just threw the code for it.

Originally Posted by Ricky21

Im getting horrible mileage to, its down to like 11.6! I tried changing my plugs,maf,font o2 and its still bad. Are you running no cat? I dono if that could have anything to do with it because its after the front o2, but I finally just threw the code for it.

Just a SWAG but I’d bet your problem is your spark plugs. For optimal mpg you need to run stock heat range spark plugs and T-stat. If you’re running a smaller pulley you might want to try AL605s, otherwise stick to AL606s.

I was thinking that, the reason I have 104s is because i plan on dropping pulleys soon and was under the impression that it wouldnt hurt for a short time

Originally Posted by Ricky21

I was thinking that, the reason I have 104s is because i plan on dropping pulleys soon and was under the impression that it wouldnt hurt for a short time

I knew it
In just going out on a limb here and am assuming you are a little mis-informed on spark plugs.
IMHO many ppl believe colder and smaller gapped plugs some how make the engine run better or have more HP. The reality is the opposite is true; you want to run the warmest and widest gap plug you can. I’m not going it the complexities of this ATM (just to add this KR ya ya blah blah spark blow out yad yad). However, at 11mpg I’d go get a set of AL606s tonight. Recovering that 12 bucks won’t take very long, so why not just do it.

So those will also run fine with a smaller pulley?

Originally Posted by Ricky21

So those will also run fine with a smaller pulley?

Or you can just hold onto the plugs and put the 104s back in when you go with the smaller pulley

Originally Posted by Ricky21

So those will also run fine with a smaller pulley?

Well, if you are going to run a smaller pulley soon I would install AL605s. They will only minimally affect your MPGs, and should allow a mild pulley drop. Every engine is different, so you’re going to want to monitor your KR just as you would for any pulley drop. But man why sweat it, plugs are cheap and easy to change. Definitely keep your 104s, but also definitely change to 606/605s for time being.

Yea thats what Im thnking Im going pick some up right now its not like its hard to switch em out anyway thanks for the help

The only thing I can think of is when I had a similar issue last year in my 2000 GTP. I had no idea why I was losing mpg's but it dropped to around 14-15 average without altering anything. Turned out my thermostat died and was constantly sending a too hot signal, forcing the water pump and fans to run continuously. Once I replaced the thermostat, my MPG's went back to normal.

This was likely a unique problem, but it's worth checking.