Hey everyone. I have a 96 XJ 4.0L 5 speed. I have a misfire that's been going on for the past week. One day it just started misfiring real bad and had no power so I limped it home and checked it with a code scanner. It turned up Injector Circuit 3 Open, Cylinder 3 Misfire, and Random/ Multiple Misfire. I turned off the CEL and it ran fine. It misfired again and and popped up a CEL so I turned it off and it ran fine. Any ideas? I'm going to check the wire for a short tomorrow, but is there anything else I should be looking for? Sorry for the long read and thanks in advance!

 

Could be injector is toast, or just has some buildup on it, they're not too hard to take out and replace I know it helped my really rough idle a lot. Or could be bad wires or plugs but If the code says curcuit is open on injector then I'd check wires, fuel pressure, and check for buildup too. I think there is a package you can buy even called injector cleaner package or something like that. I've little experience with fuel system alls I've ever done is cleaned my injectors because idle was ****. Hope this helps some...

 

I replaced and rebuilt the injectors last year with Ford Explorer #19 injectors. I tested them all before I put them in. I'm running fuel injector cleaner right now, but the light wouldn't come on for an open circuit if they were gunked up. I'm just stumped because after I reset the CEL, it runs normal until it comes on again.

 

I agree that this is electrical. Start verifying wiring for the #3 injector.

 

Mine does a similar thing, but says misfire # 4, I also have a 96!

 

Today, I checked the resistnace on the injector and it was okay along with the rest of them. I didn't have a chance to pull out the ECM to get to the plug I need to check the wiring, though. After some research, the white plug had a yellow/white wire which is the cylinder 3 injector. Hopefully I'll have more time tomorrow since I need to be at work soon. But it's still running okay for now.

 

I have started experiencing teh same "cylinder 3 misfire" recently. I talked to my local jeep experts and they told me this is a growing problem with these 4.0L engines, especially here in Texas where it gets HOT. The amount of ethynol that is now added to gas is causing the block to run hotter. Rhw misfiring typically occurs when starting the engine while it's still hot. They've tried several things to fix this (new injectors, heat shielding/wrapping) with limited success. Just do a search for "cylinder 3 misfire" in the jeep forums to see what people have been trying to do to fix this.

 

Well I checked all the wiring coming from the ECM and all is good. Everything tested out perfect, so I'm really not sure what caused this to happen. It happened twice, but it's been a few days and all is still running good. Let's hope it stays this way. But to everyone else with this problem, here's a thread that helped me out https://www.cherokeeforum.com/f2/cel...it-open-35437/