I'm still chasing this rough idle issue for 3 years now. Posted several weeks ago and purchased a new crank sensor. After install, still rough idle and now a ff24 code and limp mode. I've changed back to original crank sensor, still FF24 and limp mode. At least for the last 3 years, I never went into limp mode, but I also never got a code. I've just acquired a good used ECM and plan on installing that next week. Any other suggestions. I will also clean the idle control valve again or replace it with a spare that I have. Help, I want to try and drive this Jag. again.

 

I've had this happen twice to my 1996.

No matter what I do, the only fix is taking it to a local Jag shop that has a PDU.

There's one in Minneapolis. I would bet a lot of obey that that will cure what ails your car.

I have a working IDS and I can't seem to fix it with that.

(I will admit that the second time just happened recently. I just dropped it off at the shop after chasing down vacuum leaks and checking parts)

I'll let you know what the prognosis is)

 

how's it going what is the prognosis anxious to hear how it's going mine seems to be doing exactly what yours is doing

 

They're having trouble diagnosing.

He told me that I'm getting an intermittent signal in cylinder 4 but he can't seem to make it happen when hooked up to the PDU.

Oddly enough he asked me what work have I done recently. He was rather I tested in my throttle pot, obviously. I was kinda surprised he hadn't run a TPS reset already.

Hopefully I'll learn more tomorrow....

 

I changed out the ignition module, that did not help. I acquired a good/used ECM. Before I installed it, I removed all the connectors and used carb cleaner and a small soft detail brush and cleaned all the small pins on both the ECM and the wire connectors. I did the same on the ignition module.
Reconnected the battery and it fired right up, but really ran poorly while the ECM reprogrammed itself. Ran bad for about 3-5 min. and then smoothed out. I took it for about a 30 min. drive. Drove it very cautiously for about the first 10 minutes waiting for the limp mode to kick in, but it didn't. Then I decided to drive it harder to see if the ECM would hold. It appeared to work fine. I haven't been able to drive it since, but so far, so good. As I stated, it drove fine for over 30min. and never went into limp mode and never posted the FF24 code. I will let you know if the code comes back or if has been fixed. (((The idle is still not perfect, but seems to be better)))) If it keeps running correctly, I'm going to live with the minor idle issue alone. Leave well enough alone and drive it for the remainder of the summer.

 

Put a new air filter in it?....