i got a 92 civic hatch with a d15 auto tranny and im getting around 12-15 mpg which definitely blowss!!! i got a cel code 43 after driving for a couple minutes which sends me to fuel system....yes ive searched but i havent found a definitive answerr....code mostly leads to o2 sensor but honetly i dont think an o2 sensor would cause me to drop 20 mpg overnight! where should i start? what parts should i be looking to replace?

 

I threw the same code on my car and my car gets significantly lower gas mileage. Replace that first and go from there.

 

If there are no performance problems, then the O2 sensor is the first place to start troubleshooting.

 

how did u fix urs when the code came up?

 

well actually going up hill i cnt even get past 20mph and it lags to pick up hwy speed. i know that that a d15 is SLOW but its gotten worse ever since that code came up. since i have lost performance what should my next step be?

 

Do as the code states. Replace the bad o2 sensor... Problem fixed, you should also do a complete tune up if it hasn't been done in a long time
-plugs
-wires
-cap/rotor
-Pcv valve
-fuel filter
-air filter

 

well actually the honda manual branches out the code into 3 sections 2 lead to the o2 sensor but one leads you a different way if performance took a hit. which o2 sensor should i replace?

 

Have you replaced the fuel filter?

 

i did and it didnt make a difference. sometimes it feels like its not passing on gas so i was thinking about installing a gas pressure regulator and c if that takes me somewhere..what do you think?

 

Measure the fuel pressure and test the FPR while you're at it.

Are the fuel injectors gummed up?

 

What's the "last" lead? The code should tell you which sensor. I'm pretty sure it's the primary 02.

 

how can i check the injectors?

 

it takes me to pages 11-89 which is actually a little unclear to me. ive read threads that tell u to change gas cap fuel filter threads that even tell me its the fuel pump but if my fuel pump was failing shouldnt my car shut off randomly?

 

Remove and inspect.

 

lol obvious right...sorry i dont know how to take em out and check em.

 

Remove the fuel rail.

 

ok well am a take a look at em but should dat drop my mpgs by 20?

 

A problem in ANY part of the fuel system could dramatically affect mpg -- pump, FPR, injector, fuel return. The O2 sensor also is not ruled out.

 

thanx i appreciate the help am check the injector and ill get back wit some pics of they are.

 

^THIS

your car NEEDS an 02 sensor, the CEL isn't lying. Stop beating around the bush by changing parts that your just guessing it needs, like the fuel filter. start with what you know to be faulty...its cheaper to replace parts that are not working, then guessing what might or might not be wrong.

 

Code 43 does not necessarily mean that the O2 sensor is bad. I'm not saying that the OP's O2 sensor is fine, just that the fuel system must be seriously considered when there are performance problems, and there are.

 

^^^ thank you, sir.
exactly what manual says. i do get that o2 sensor can affect performance but i dont think that a 20mpg drop would be caused by an o2 sensor.

 

I personally would not rule this^ out either. Keep an open mind and you'll find the problem more quickly.

 

well am definetly keepin an open mind...i got to i mean gettin 12mpgs sux. i got an extra o2 sensor so im a replace it and c if anything changes. the extra 02 sensor i have is the one that goes before the cat not right on the headers is there any difference between the 2 besides the longer cables?

 

Not sure. Maybe somebody else knows.