Rep Power: 0

Hi, I just returned from a vacation of 3 weeks. I started my 1997 honda civic and the check engine light came on. It started a bit rough. I did the paperclip trick and got two CEL codes:

72: Cylinder 2 Misfire or a Random Misfire a condition is present that is creating a cylinder misfire
74: Cylinder 4 Misfire or a Random Misfire a condition is present that is creating a cylinder misfire

My vehicle has only 240,000 km. The spark plugs were pretty close to needing a change.

My questions:

1. What is the most likely reason ? What is the first thing I should do? I am guessing replace the spark plugs ?
2. I shouldnt drive the car ?

Thanks, Julian

 
Rep Power: 221

As long as the light isn't flashing with the engine running you're ok to drive. I would start with the plugs, buy ngk

 
Rep Power: 0

I reset the ecu by removing the fuse, and the engine light no longer came on. However, now it has a rough idle, very rough, going from 1000 to 2000 and dropping down. I am not sure if this is because i didn't follow below 7 steps, I just unplugged and started right away. Would this cause a rough idle if I didnt follow 7 step procedure. Or perhaps it is because of spark plugs ?

1. Go drive the car around and get it up to operating temp.
2. After you come back with your engine at operating temp. turn it off. Unplug the fuses (ECU and ECU Back up fuse)
3. Wait 10 minutes.
4. Put the fuses back in.
5. Start the car, its important you do NOT touch the gas pedal at all! Just let it idle for 10minutes!
6.After 10 minutes of idle, turn off the ignition.
7. Wait 2 minutes.- This saves the new corrected data/settings to the ecu!After those 2minutes, start the car and go for a drive.

 
Rep Power: 366

idle relearn procedure.
redo

after reset, ECU is a baby. Let it learn how to walk

 
Rep Power: 0

Googling idle reset for my car, I seem to find several reset procedures. What is the best way to do this, with the 1997 honda civic ? Thanks Julian

 
Rep Power: 0

I tried the following:
1. Turned off electrical in the car.
2. Pulled out FI-ECU for 15 min
3. Turned on Ignition for 2 sec.
4. Started engine and rev to 3000 rpm in park.
5. After coolant fan came on I let idle for 5 min. During that 5 min, it idled from 1000rpm to 1800rpm , back and forth.

Not sure what to do next ?

 
Rep Power: 221

Just disconnect the battery, wait 15 mins, reconnect, start the car and let it idle for 15 mins, keep the interior fan, stereo, any lights, etc off

 
Rep Power: 0

I disconnected the battery and waited for 15min. I reconnected and started the car. It idled nicely for about 30sec and then started idling from 1000 to 1800 for the next 14 minutes. When in drive everything runs smoothly. Just in neutral and park it idles back and forth from 1000 to 1800. Not sure what to try next ? I have changed spark plugs and will change spark plug wires next week.

 
Rep Power: 221

Clean the iac

 
Rep Power: 0

After a couple of days driving the idle has retuned to normal. No more surge in neutral. I am guessing the problem happened because it was sitting for 3 weeks without starting, everything was cold and maybe sticking. Probably the IAC needs cleaning but I think ill wait until i change the coolant in a few months. I was thinking in the meantime I should put some additive in the fuel to clean up any carbon ? The ATS 505 seems like a good choice ? I am just starting the learning process in terms of mechanical work so I am not sure if this makes sense ? Any feedback is appreciated. Thanks.

 
Rep Power: 0

Did an oil change. Turned on the car and I got the engine light again. This time is was code14 IAC Valve (Idle Air Control) defective circuit or unplugged / defective sensor.

 
Rep Power: 366

then you already have the answer