I recently bought a 95 Civic Hatch VX with the Vtec-e and 97k on the clock. Lately it has been hesitating very badly at anything under 1/2 throttle between idle and 3200RPM This happens in any gear and any weather condition. A few days ago it threw a CEL but when I went to ck it the cel it stayed solid. Now I didn't see anywhere in the FSM that it meant that anything was wrong, so I figured it wasn't a hard code. I checked the voltage on the o2 and it seemed to be reacting slowly, but, ive never dealt with this type of o2 before so I wasn't sure what to look for. Today it threw a hard CEL , code 48 LAF sensor. Now my question is..... since I'm at work and don't have my FSM in front of me, what is it , where is it and how much is it to replace? Also it sounds like its the same as an o2 and if it was why wouldn't it throw other cels? Like a o2 CEL?

 

That's your lean air fuel sensor... Ignore that code, most probably you have a problem with the o2 sensor and your ecu it tripping code 48.. common problem with that code.

Test o2 sensor this way:

1. warm up car to operating temperature
2. tap into signal wire of the o2 sensor with multimeter.
3. rev car to 2000 - 3000 rpms for about a minute or so - o2 sensors don't work unless they are 600 degrees farenheit in temperature.
4. Let it come down to idle, and you should see a rapidly changing reading, typically between 100 and 900 mV.

No voltage, a steady reading, or slow switching (a common rule of thumb is eight trips across the lean/rich line in 10 seconds) means the sensor is probably the cause.

fs

 

Thanks! Thats really good info. I will Let you know how I make out.