ok guys, i have a 1997 civic coup ex auto and im getting 25 mpg hwy.. did almost every thing full tune up, new plugs wires , cap , rotter, fuel filter, air filter , new o2 at the header, new struts and shocks, that helped some what, the only thing left is the cat..should i drop the 250-300 for a 2.25 cat? any ideas?
thanks...

 

How are your driving conditions? Do you beat on this car at all? Or drive it like a grandma?

 

just remember, if you want mpg, more performance = less mpg.

 

hahaha you suck at driving!!! jk

 

Is the cat clogged?

The motor could just be beat, vacuum lines could be torn, do you burn or leak oil?

 

no a cat's ability does not affect the fuel economy, the only way it can affect it is if its clogged. don't buy a cat. becuase its an obd2 vehicle get ahold of a good scantool, and you can pull up the long term fuel adaptations to see if they have creeped over to the rich side. i am implying not rich enough to throw a code, but rich nonetheless. if it is nto rich, look for a fuel leak external of the engine, or under the car, or something, if it is richening, look for either a restriction of fuel's ability to enter the motor, or the moter getting false air taken in, [vacuum or secondary air] leak.

 

You didn't mention tire pressure, condition, or alignment, and those items affect your mileage more than anything else.

 

ok heres the deal its a shoc d16y8,140,000 on her.
wtih dc 2in" headers, 2.25 cat back with vibrent stealth muffler. not a fart can.. engine runs like a champ, compression is fine on all 4 cylinders, my tire psi is 37psi 40 (when its hot) on all 4.
so far the thing that help bump it up 4-5mpg was the new kyb agx shocks ive dropped in. shes sitting on stock tire size 185/65r/14 and 1.4 in" lower with eibach pro kit springs, and the alignment shop got her dialed in at -3 degrees of camber, drives like its on rails...
and yeah ive tested driving like a grandma vs. a heavy foot trying to get the vtec to kick in, some times it does some times it does not kick in, and not much difference in mpg the highest ive reached was 29 mpg driving like an old lady...
i do believe shes running rich just from how the old plugs look, but yeah ill try hooking up the obd2 scaner, auto zone still lones them out rite?
i cant hear any vacuumed leaks and deffnotley no fuel leaks, would maybe clogged injectors be part cause? or fuel pump is going bad .... thanks for all the help guys..

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by raulduke &raquo;</TD></TR><TR><TD CLASS="quote">so far the thing that help bump it up 4-5mpg was the new kyb agx shocks ive dropped in.</TD></TR></TABLE>

I heard brake disc grease and a set of these will really improve mpg:
http://img402.imageshack.us/im...2.jpg

And no, AutoZone won't lend you a scan tool, but the will do the scan for free. Remember too that 55-65 mph is the "sweet spot" for best mpg on most vehicles, so if you drive at say 85 mph all the time your not achieving the best possible mpg.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by mcvtec &raquo;</TD></TR><TR><TD CLASS="quote">

I heard brake disc grease and a set of these will really improve mpg:
http://img402.imageshack.us/im...2.jpg

And no, AutoZone won't lend you a scan tool, but the will do the scan for free. Remember too that 55-65 mph is the "sweet spot" for best mpg on most vehicles, so if you drive at say 85 mph all the time your not achieving the best possible mpg.</TD></TR></TABLE>


lmao ^^^^ - but yea, just remember with those headlights...you need the proper headlight fluid to achieve optimal mpg

 

i am having that problem too. i have a 1995 honda civic with a b18b1. any suggestions anyone?