XJ6 XJ40 IDLE SURGING 900rpm - 1500rpm

Hi all pretty new to Jaguar game. Have had this xj40 xj6 for a year now loving it with no issues till now.
Recently I had an engine light come on and off intermediately but with no issue, the VCM gave me the code FUEL FAIL 46 and sometime FUEL FAIL 47 but never effected the drive.

Till just the other day I drove to the shops (no issues) turned the car off and when I turned it back on it was stalling not even holding revs for a few second, I managed to turn the allen key by the IACV which allowed me to move it too a spot I could get towed - since getting it home I suspected it was related to this IACV motor (stepper motor) I have ordered a new one and waiting for it too come in but just wanted to know if anyone else had experienced this and could confirm if these symptoms are related to the stepper motor. I have read alot of mixed comments on it online but based on what it is doing now.

So I have uploaded the video but basically I took the Stepper motor out and cleaned it - disconnected the battery to reset the ECU and put the same cleaned stepper motor in - now it idles and doesnt stall, but idles terribly surging from 900 - 1500 RPM

I am waiting for the new Stepper motor and hopefully i pray that all it was but just wanted to know if anyone had any advice on this based on the above context and if anyone could confirm if I am correct to think it is the idle control motor.

the cars done 163k km and in very good condition was always parked indoors by previous owner, I also cleaned the MAF, and throttle body (which was already quite clean)

Any advice or experience with this would be appreciated - my main car knowledge is around 90s JDM turbos so new too the AJ6 engine

I have also read online that the new stepper motor needs to be reset ? as per AJ6 FAULT CODES AND IDLE SETTING / AJ6 Engineering

Is this true ? As I have also seen posts online saying it doesnt but just wanted advice based on what its doing with the cleaned stepper motor.

Video of surging after cleaning Stepper motor (- YouTube)

I haven’t had that particular problem but it does sound like you are on the right track considering the specificity of those codes . Your engine looks very clean and well kept But while waiting you might doublecheck the TPS pictured. While not specific to idle control its location under the throttle housing means it can be fouled with oil and give bad readings to the ECU.

tps

Yes it does need to be reset. Follow the procedure.

No idea what these are? Country specific?

Thanks for confirming will do once the new one is in, looks fairly straight forward.
90s JDM = Japanese domestic Market, 2L turbo world - the evo’s, wrx’s, skylines.

thanks for that, good to know - will definitely double check too.

Welcome to the forums Varun, just to save you some typing you can reply to numerous posters in the one listing we aren’t too precious that we can’t share😀
What can help sometimes is to place your flag of residency in your profile.