I am going to lose my mind with my XJ. I have been dealing with the intermittent misfire and crappy idle.

I have replaced all ignition parts(cap, rotor, wires, plugs-with champion copper) seafoamed it a few times, etc.

Sometimes it will idle pretty good, sometimes it feels like it is going to die. Yesterday i was dropping my daugher off at school, it was idling like complete crap. So after i dropped her off I was at a light getting pissed at the way it was running. I floored it and when I stopped at th next light and for the rest of the day it ran and idled pretty good. this morning, same old caca, idled ok, then progressively got more annoying. Like I said, some days it will run fine, then for 2-4 it will run like crap, so on and so on.

I have the on and off check engine light for cyl 1 misfire, depending on the moon and stars it will go on and off.

here are a few videos of the misfire. I am thinking of yanking the head and replacing it, and the lifters???


Engine idling...

Tailpipe with misfire.

tailpipe with misfire at a different pace(because it likes to play different beats) and stuck my hand there to confirm it sucking in...

 

check your connections on your injectors , i put some dieletric grease on it an closed up the connetion so it will fit tight . try that it's cheap.

 

I pulled the injector plugs a few months back to see if there was any corrosion, didn't see any, but it's worth a shot. Thanks.

 

burnt/stuck exhaust valves or weak valve springs causing valve float.
give away is the sucking in on exhaust. your exhaust valves are still open on the intake stroke.
most likely burnt valves. see if you cant find a remaned head and throw it on.
dont do lifters unless you plan on replacing the cam also, they match wear.

 

I was pretty sure it was a valve issue, i just wanted more reassurance from you guys on here. I am going to buy a rebuilt head next month and replace my also cracked exhaust manifold. Do the L/R motor mounts while I am at it??

Any tips or need to knows on head replacement for xj's?

 

id do the motor mounts while your at it, be easy.
only thing i remember is that you have to bend back part of the pinch seam at the firewall so you can get the head bolt out.
make sure to clean your head bolts/block threads and i believe one of them needs to be sealed because it comes in contact with a water jacket.
ill e-mail you a link to an FSM for your torque specs and pattern.
-T

 

X2

 

Got an ohm meter? Check the plug wires. Are they tucked away properly? Look kinda like they're dangling. Check everything on the intake side...all the sensors, injector connections, clean IAC port/throttle body, check for vacuum leaks. U did say u had/have a CEL. I don't see how a valve train issue could be intermittent.....runs good one minute/bad the next, as u say. However, virtually any malfunction on the ignition side (including new wires) and/or intake side can be intermittent along with tricky to find.....just takes time. If you've done all that, great, I'm just suggesting check the cheap stuff 1st.

 

Just did a dry then wet compression test. 5 strokes warm engine.

Dry
1 150
2 162
3 160
4 130
5 165
6 165

Wet

1 154
2 164
3 162
4 130 SAME!!!!
5 165
6 165

So.... I did a half assed leak down test. Brought cyl 4 to top dead. Hooked up my compression hose, used my small air tank and let it blow into the cyl. I heard the air in the exhaust when the wife pulled the trigger on the tank. Nothing out of the intake. Dead valve or bad spring confirmed. New head in November.......

 

I also pulled the plugs on each of the injectors and tested them all. All were at 12.6 ohms. When I had it running, I pulled each one while it was running. All cylinders from 2-6 made the enging idle worse. Cylinder 1 made NO difference at all. All of 2-6 you can feel/hear the injectors open and close, injector 1 I felt nothing. So i have to yank that out too when I do the head. Lots of fun ahead.

 

Thanks for the link and help. I see where that last rear bolt is difficult. It's the one for the intake/exhaust that looks like a real pain.

 

did you ever fix this problem? mine is the EXACT same with with the exception of the misfire being cylinder 4 (comes and goes as it wants); what drew me in was my exhaust sounds the same way. thanks for any updates.