My quest for decent gas mileage in this shitbucket continues. Here is a current list of parts that have been replaced in the last year:

primary and secondary oxygen sensor
pvc valve
exhaust manifold
fuel filter
spark plugs
spark plug wires
air filter

Gumout fuel injector cleaner and Lucas fuel injector cleaner has been ran through the car for the part two fill ups. Only modifications are as follows:

2.5 exhaust
crappy air filter
1.8l ECU
Beta II motor

On the highway, with the air conditioning on, I can barely break 23mpg on all highway driving, and with it off, I can break into the 26mpg. Most of the driving is 50/50 of city and highway, no mashing the throttle, just normal driving. The only thing I can think that can be causing this somehow is the 1.8l ECU which leans the fuel trims out. But that should help mileage. I'm at a lose of what the issue could be. Any thoughts?

 

I constantly received 20-22 mpg on my Tib the entire time I had it. I always calculated my gas mileage. A lot of it will depend on the terrain in your area. Nashville is full of hills, so i'm always going up hill

the most I ever got was 33mpg... and it was 200 miles one way, 100% interstate, and I was following another car the entire time (drafting) and doing 65-80 the entire way. I've made that exact same trip hundreds of times (home to college and back) and never even broke 25mpg

 

dang that is pretty bad gas mileage.. i got like 24mpg city and 28mpg highway when my tib was boosted. although michigan is pretty much flat everywhere so your never going up or downhill.

but even in the 'neon' i get about 22mpg city and 29-30mpg highway down here in ABQ and your ALWAYS going up or downhill and we are at 5000+ feet and thats with ethanol in the fuel.

which shit bucket are you talking about that is getting the bad mileage?

try throwing a 2.0L ECU in there just for giggles and see what happens.. seems like you got all the bases covered with what you have replaced and you should be getting like 30mpg+ on highway EASY.

 

This is in my Elantra. I've done everything I can think of minus throwing the 2.0l ECU back in, I'll give that a try.

 

You know, you might want to try a decent intake instead of just a new filter. I know I wasn't gettingmore than about 26MPG on mine till after my AEM. Now, with everything I've got done, I get about 32 to 36 MPG, every time.

Oh, also, check to see if nay of your vacuum lines are clogged, and check your pCV valve, when taht stuff gets clogged, cars run like shit.

 

MSD coil, wires and dis-2 works wonders.. well it did on my tibby and my moms sonata it has MSD 6T, blaster 2 coil and MSD super conductor wires same as mine and HKS plugs.

i also noticed a improvement in the sonata when i changed the o2 sensor, injectors, FPR, and coolant temperature sensor.. i can go almost 550 miles on a half tank if i keep it at 60mph, but also keep in mind guys the gear ratios play a big part in this.. for the tibby if you want to cruise at 60mph at 2500 rpm you will need to run a FGR of 3.056

 

and just how do you get a FGR 3.056?

 

to clean the engine you could use Sea Foam ? i find it work really good... don't know what poeple think about it....

how is your clutch ? sliping a bit ??

Tranny is one thing to that bother me about the Tib on highway at 120km/h at like 3300-3400rpm
way to high

my fathers matrix wich is automatic at same speed engine is at around 2800rpm sad.gif

 

lol, MJ. great idea.. spend around 600+ on the MSD setup, and 500+ to get a different FGR, to get better mileage. would take like 2 years to actually pay off the MSD, FGR setup and start saving from the better gas mileage.

 

I will hook people up.. but the msd is the way to go..