Bad Injector?

Hey all.

After driving my 1990 240SX hatch less than 65 miles since last full fill-up, I filled the tank up again because I was curious as to why the gas guage was halfway down already... 65mi/5.3gal figured to only go about 12 MPG!!!

I don't think its my driving style... I'm kinda new to manual tranny and I always try to shift between 3-4k RPM.

There used to be a gas leak problem where the injector feeds into the engine but an O-Ring replacement removed the liquid leakage. The check engine light goes on and off without showing trends. The engine was either replaced or rebuilt. Some friends say it sounds pretty bad sometimes and normal at others. I am not too sure what is going on. I'm handy but fairly lacking in car knowledge.

Oddly enough, my dad drove the car from California about a year ago ... with 12 MPG, he might have had to fill up 3 or 4 times between LA and PHX, but I don't think it had the problem back then.

Anyone experience this with their little beauties? Any help/suggestion is greatly appreciated.

shift at 3-4k rpm?
that's kinda high I think

I shift at 2-2.5k RPM cuz i try to conserve fuel and keep noise levels down(I dont have a muffler+gutted cat=real fucking loud)

when ever the light goes on do you check what code it is?

I'm gonna be as newb as I can :P

Not too loud on this one. If I shift around 2k I get a low rumbly noise that I don't like to hear; will shifting there cause the transaxle to strain and damage? I sometimes just let it coast on Neutral after going 5-10 over speed limit or when I know I'm going to stop soon anyway. Is it safe to pull it out of gear without hitting the clutch (ie: 3rd to Neutral without clutching)? It allows me to do it on all gears but I'm unsure if it will damage so I ceased.

I don't know how to check the code... do I need some specific tools?

get a owners manual it tells ya when to shift too lol....anyways try some seafoam and hopefully it will clean up any buildup...but yea i usually shift at 15mph, 26mph, 36mph, 45...which is under 3k

What transaxle? It's rear-wheel drive! Oh and by the way, there's a clutch there for a reason, I know it sounds silly, but you can use it sometimes.

get a owners manual it tells ya when to shift too lol....anyways try some seafoam and hopefully it will clean up any buildup...but yea i usually shift at 15mph, 26mph, 36mph, 45...which is under 3k

Thanks!

What transaxle? It's rear-wheel drive! Oh and by the way, there's a clutch there for a reason, I know it sounds silly, but you can use it sometimes.

Or driveshaft, I wouldn't know. Oh really? But the car doesn't seem to move forward when I hold the clutch in!

Holding the clutch pedal down is just like putting the car in neutral...

I shift around 3500, I'm really mean to my car though >=)

3K is a nice optimal shift, shifting at 2500 seems pretty low =\

yeah, if i shift at 2500, i sounds like the car is underpowered, usually 2700 or 3k is best for me, optimal power, good gas mileage. and if im pissed or late, 4-4.5k is usualy good...racin, 5-5.5 cuz the power pretty much cuts out at 5 anyway