I have had a full service, new elbow pipes etc new gaskets, new coils, ecu reading states no problems.
Car management light comes on now and then, rev counter goes up and down at standstill, car judders when you drive it.

Tried poss problems , air leak, spark plugs, coils, gaskets, air hoses... ALL CHANGED.

I am now at a complete loss any ideas please as i am ready to slit my wrists

Car ... S type v6 year 2000 .... 51000 miles

 

Is it the same wit the aircon off?

Otherwise sounds like a vacuum leak. Sure everything is connected?

 

yes same with or without air con all connected , driving me nuts !

 

Stop changing things and take readings. OBD live data for such as fuel trims at idle & 2500rpm. Check O2 waveforms. That kind of stuff. Make sure battery is not old (no, you can't test them).

 

battery new,........ no fault codes coming up hense at a loss, i am not that tech to have a scooby what you just asked me to look for im afraid.

 

Find someone fit to work on the car who knows what OBD II is. (Unless you want to spend lots of time learning it yourself.)

 

if obd 11 is where they put it on car to read faults i have had that done twice by two diff mech costing £40 a pop and both said no faults come up ?????

 

See post #4

 

Find a mechanic that specializes in Jaguar.

 

lol

 

I'd say tech not mech.

 

i have had enough of it tbh what price do you think i should try and sell her for with this problem ? year 2000, silver good condition 51000 gen mileage cheers

 

When it comes down to where you are with it, what is suggested in this post is really in my opinion somewhat for the real knowledgeable guys and a tech and probably the issue. Not that you could not figure it out but it can be a daunting task. I had this same issue a while back and knew I was not qualified to get it correct. No codes were showing up either for me. Jag tech is the way. Also I am sure you have the right one, but just in case, did you get the right battery. Cannot stress enough you do not go cheap here. If you were in the states I would be interested. Good luck.

 

ok last chance for ice lollies lol ,,,, what is and where do they go IMT rings i have read loads of posts saying this is common fault, as the car revs up and down at stand still and i have replaced every thing else that it could be , well i think anyway lol might as well give these IMT rings a go !

 

Ya got an exhaust leak before the catalytic converters, out of range O2 sensor(s), or MAF meter is shot. This'll explain RPM fluctuations whilst in neutral.

 

I know you mentioned the plugs and coils were changed - just curious... did you use OES items (Jaguar Coils and NGK Double Platnium Plugs) - or aftermarket items? Most aftermarket plugs will affect drivability and as far as coils - there are some cheapie coils out there - that will wreak havoc once installed. If your "car management light" comes on and flashes worse yet - definitely a misfire situation. Just throwing my $0.02 on the issue as some food for thought but indications are IMT O-Rings - OBD II codes will point you in the right direction, thanks!

 

after market coils fitted , all i need now is someone near me to lend theres and see if it makes any difference as i really don't want to buy new ones again before i know, reader saying no codes which i have no explanation for . it would make sense as the new ones when put on stopped all faults but all came back after about two weeks ?

 

When the coils were changed did you notice any oil on the old coils or in the spark plug wells? If there was any oil this would be indicitive of your spark well rubber gaskets leaking oil into the spark plug well - oil can easily crap out an even new coil in a very short period of time. If you did have oil in the spark plug well you will need to have your cam cover gaskets and spark well gaskets changed out. Depending on the brand of aftermarket coils - you could have received a faulty or poorly constructed one - it has been mentioned on the forums before after installation of aftermarket coils.

 

Do you have an OBDII reader to install in the car as you are driving to see if any codes come up? Are you getting a restricted performance or failsafe indication on the dash?

 

Another consideration is to have your tech test the voltage output of the aftermarket coils. Sometimes you can have enough variation with aftermarket parts that this will play havoc with the engine computer.... and cause all kinds of weird things to happen. Have you tried replacing the aftermarket coils with the originals and see if that changes the behavior? Just a thought.