Hi new to the forum just bought this car and looking for help on what to replace i dont have much experience. So the problem is when i start most of the time it idles bad then i give it gas for about 10 seconds and then its alright. Was going to replace the injectors but i figure it could be a lot of things and wondering if anyone on here had any ideas about what it could be if they had a similar problem. If not i’ll do injectors then pump but i have a fuel filter on the way that ill replace to see if that helps. Any advice appreciated, thanks

 

Throwing parts at a kitty is not the best way to get her purring again. First, use an ELM327 and torque app (least expensive way to get basic information) to read if there are any codes. If there are, use SEARCH in this forum to research as nearly anything and everything has been discussed ad nauseum here. Start there and then progress.

 

Zoombo, like what Dell said, get yourself an ELM327 unit, it will save you a lot of money and time.

As for your problem, I would say to first start with getting a can of throttlebody cleaner. You then can remove the intake hose off of the throttle body and if you see brown, spray it away. Make sure to use your finger to open up the throttle body to spray in there. Also, make sure to get the edge of the silver disc (referred to as the butterfly). Some of these spots you may want to wet a cloth and scrub. But, you want to get rid of as much brown that you see as possible. Now, odds are, if you used even half a can, the car is going to be flooded at this point. To recover from this, you are going to get into the driver's seat, press the gas pedal down as far as it will go, and then start the car. After 5 seconds of the engine rolling, ease up on the gas pedal a little bit and bring the engine to idle.

I know what you are thinking, flooring my car when it start it is going to cause it to rev wildly. Not with computer controlled cars. Flooring the car during a start actually turns off the fuel injectors. Then as you ease off the gas, it will start admitting fuel again.

What you are most likely experiencing is a build up of gum/tarnish on the edge of the butterfly and this is causing drag to occur. This causes the butterfly to not be able to move freely to control the idle. Hence why the idle is bouncing all over the place. As you get heat in the car, the gum gets mushy (like warm taffy) and the throttlebody can then push through that.

 

Thank you guys i will get that and try the spray on the butterfly. I just drove it 100 miles to see if check engine light would come on cause i just bought it and the guy i bought it from was a shady character. No light came on and only code that came up from my autofix was a p1000 but today its gone.

 

Zoombo, yes, you want the P1000 code to go away. Granted, I would be asking why our car had that question to begin with P1000 is simply stating that you Jag has not done a check of all the emissions systems to the point that they are considered functional. Normally this happens after you clear all the codes or you remove power from the ECU and then repower (which requires the car to relearn evertyhing). What you are wanting to see is a P1111, which says all has passed and the car has no issues that the computer can see. Normally the P1111 code will not show up, but some readers do show it.

 

Thermo thank you for the throttlebody cleaning advice, no idling problem at all anymore! There was tons of crap clogging it and it took me no time to clean it. Thank you, passed smog last week

 

I can only speak from experience of having this era motor on idle myself, the engine hates heat. Mine pissed oil everywhere, keep changing the oil, check the ridiculous small fan and radiator are even working! It will get you there fast, but as everyone on here is from the sunshine state? Well done for having a XK8? I’ve seen one running in England!

 

This is wise in my limited opinion and agreed. Could be as simple a throttle cable replacement?

 

Bianco77, the X-Type does not have a throttle cable. The X-TYpe is a drive by wire setup. There is nothing that physically connects the gas pedal to the throttle. So, the resistance that you are feeling is just a spring. Nothing more.

 

Ok, sorry I wasn’t aware of that, the problem actually (in my head) reminded me of my first car, Pug 106 1.4 which had everyone look at it, had a bunny hop thing where you had to ride the clutch, it just occurred to me, everyone I took it to was completely baffled. Sorry for my lack of knowledge, this site is teaching me lots tho. Thanks 😊

 

Bianco77, do not feel like i am putting you down or something of the sort. Not trying to do that. Just trying to make sure that facts are put out so we don't battle some of the mis-information that is out there these days. Much easier to learn something correctly the frist time than to try and unlearn something and then learn it a second time.

 

was wondering if you thought that, I’m not at all put down! Tell me when I’m wrong!

 

A bit of humour......You're both right actually....
The 2.5 and 3.0L X-Type petrol engines are drive by wire (Thermo you are entirely right), so too the Diesel engine variants, but the 2.1 V6 X-Type does actually have a throttle cable (so Blanco, you are also partially right, but in this case not correct for the original poster's engine type).