I'll try my best to describe the issues I'm experiencing. I have a 2001 Jaguar XJ8 Vanden Plas. I've noticed it hasn't been getting great fuel economy for quite some time now. The car always starts like a hot damn in the morning, but once you turn it off and park it for say 20 or so minutes or more, the car will struggle to start and will usually take 2 or more tries to get started. If you try and start it witin a few minutes of turning it off then it will start just fine. Once the car has sat for a much longer period of time (such as overnight) it will start again first try no problem. Could it be the fuel injectors? Thank you!

 

I would be less concerned about injectors and look at the simple things first. Check the plugs, how clean or dirty and their gap. Check your MAF, don't touch the filament. If you clean it, use only a MAF cleaning spray. When did you change the air and fuel filter last? Then if none of that helps, then we can dig deeper.

 

+1, doesn't sound like injectors.
Beautiful car by the way!

 

Thank you for the tips. I will look into your suggestions!

 

Check your fuel pressure at the schrader valve on the fuel rail, sounds like it is not holding pressure.
Vector

 

I've cleaned the MAF sensor and cleaned the throttle body. After doing this the car did appear to drive a lot better, but really had no effect on the starting described above. In fact it almost seems like it made it worse. It still starts like a hot damn in the mornings, but as soon as you park it and turn it off it will instantly have a tough time starting (but will always start after turning the key two or three times). I still have to look into the plugs (I have a new set that will be installed). I have a brand new fuel filter waiting to go in, and when I looked at the air filter it looks like it needs replacing. I'm determined to get to the bottom of it.

 

I've had similar issues with cars in the past. In one instance it turned out to be a faulty coolant temperature sensor. It was giving the vehicle computer an incorrect temperature in certain instances which was causing the wrong amount of fuel to be injected when starting. It may not have anything to do with the CTS in your case, but it's a $15 or $20 part and takes 5 minutes to change; easy to rule out...

 

New plugs, new fuel filter, and new air filter will all help, but I like the the temperature sensor being at fault. If it is stuck, the car acts like it is cold and starts like gang busters; but warm, it thinks it is still cold and it is over rich, almost to the point of being flooded.

 

I wouldn't rule out injectors all together, however it is less likely they would be the issue. As stated before, start with the simply stuff first. Fuel filter, check fuel pressure ( fuel pumps have been a common issue as these cars got older ) spark plugs, etc. I have also seen MAF's fail and will have multiple symptoms from running rough, throwing check eng light with lean codes, not accelerating properly.


Start with the basics and move forward.

 

I have had the opportunity to do much more troubleshooting due to excessive rain the last few days, but the car did throw an engine light today. I pulled over and hooked up the reader and it said, "P0171 System Too Lean (Bank 1)." I cleared it and went on my way. Perhaps this will give another clue.

 

Check the air intake pipe. Especially the underside of the bellows. Yes, I know that it should also throw a P0174 for bank 2 lean if it's a bad air intake. Could also be lower intake manifold gaskets. You will need some brake cleaner to spray around possible vacuum leak areas while the engine is idling to see if the idle goes up. Ideally, the correct way is to look at STFT on a scanner while spraying.

 

Update: The car has had intermittent poor acceleration and will occasionally throw me an engine light. All the above problems are still happening with the car regarding starting, poor fuel economy etc. I've attached 3 images of the codes I got on the car. Hopefully these will give a clue to somebody to help further diagnose the problem. Thank you in advance!

P0333 Knock Sensor 2 Circuit High Input (Bank 2)
P0171 System Too Lean (Bank 1)
P0174 System Too Lean (Bank 2)

 

Sounds like a vacuum leak, either most obviously from an old hose or manifold leak thereof.

 

No, I guess it is a knock sensor, sounds exact the same as for Euphonium01 a couple of months ago.
Tried to find the post for you, but failed to find the one where he succeeded, maybe it was a email from him I received.

A failed knock sensor only triggers a light if the effects run out of range, but don't trigger a light just for the fact they are broken.
However, they retard the ignition, creating the exact problems you mention on power restriction.

 

Just a little update message. The car has continued to start normally in the mornings and have struggles at all times throughout the day. Usually 2-3 cranks to get it started. That is until I smacked the fuel filter a couple times last night. Started normal this morning and started first try every other time today! They were weak starts but first try! I have a fuel filter ready to go in, just preparing for the job.

 

I just wanted to post an update! I found the culprit. It was a bad fuel pressure regulator. I picked up a parts car, switched the regulator to my daily driver, reset the computer, and she was fixed! Starts strong the first time every time!






Parts car on left, daily on right

 

Your parts car looks like a better condition car than my daily driver!

 

There is just something classic about a crisp B&W photo.