I have a 98 civic ex that reads a cylinder 1 misfire, a cylinder 3 misfire, and a random misfire. I have replaced the spark plugs, wires, distributor, cleaned injectors. cleared all codes and it still keeps reading the same thing any ideas?

 

How is your fuel pressure?

When was the last time fuel filter was changed?

Random misfires are almost always due to a fuel issue. 94

 

the fuel pressure is good but when you unplug one injector at a time cylinder 3 dont drop as low as the others

 

Plugged injector, or injector is not "firing", check for power at the injector, [lead that is the same color at all four injectors] should be hot, [12V+] with ign. switch in run and start, check for a ground pulse, [from ECU/ECM] at the injector, [lead that is a differant color at each injector, you will need a noid light, or an LED type test light will work.

Switch the injectors, [3 and 4] and see if the problem fallows the injector. 94

 

ive switched injectors around and its always cylinder 3 ill go out and test the leads in a bit and let you know

also would just a normal test light work

 

Do not use a normal test light to test for ground pulse, you can use it to test for power.

The ground pulse from the ECU/ECM is low current, a normal test light can damage the injector output of the ECU/ECM.

If you have a 12V LED from an alarm or something, you can use it, even a small normal bulb like a 194 or 168 can be used to test pulse...





Straighten out the small wires, and stick them into the injector plug, unlike an LED it makes no diff. which wire goes where. 94

 

i used a led test light and it pulsed on the different color lead and the same color lead had power both running on with key turned on