Hi…. Recently, when I cold start my Jag, it shakes and acts like it is going to stall out. If I try to back out of the garage right away, my braking system stops working as if it has stalled out, but it is still running. BUT, if I sit for about 10 minutes and let it warm up, it runs fine. Before, I was able to hop in and go without warming it up. Once it stops shaking, it runs fine. I don't live in a cold climate. The coldest weather so far is 50°. My car has 135,000 on it and has never had a tune up…just oil changes, filters, etc. No sparkplug changes….could it be that?

 

I would begin by scanning the OBDII system to see if there are any "stored" or "pending" codes. You might find some P030X (misfire codes) I would certainly recommend changing out your spark plugs for sure (odds are they are more than likely worn at the least) - then I would consider investing in a set of coils.

I know this applies for the 00-02 S Types but if you see any evidence of oil residue on the coils you will need to invest in new cam cover/spark well gaskets.

I would also invest in changing out that fuel filter and air filter if they have seen 10K miles/1 year or more mileage/time.

Final point on oil - what grade are you currently using? I would think 5W30 would be suitable for your region - if your using 10W30 or higher this might be part of the issue. Again, ensure you follow Jaguar oil weight specifications.

Your shaking at start up could be VVT related and as the oil warms up and the oil thins out the oil "pressure" becomes sufficient to get through those small VVT passages. For your next oil change I would recommend Engine Flush & run through engine at idle for 20 - 30 minutes before getting the oil drained.

Just my $0.02 - Good Luck.

 

Oh no, for dog's sake, change them now, please!
Back in 1989 Bosch was introducing their platinum spark plug, claiming that they were "the only plug you will need for the life of your car" I foolishly bought them and ran them until at 127k miles, the plugs shattered. The ceramic insulators cracked and fell apart into chunks, which bounced around in side of the cylinders, taking out two valves and scoring the wall of one cylinder. You can imagine it was a lot of work to get the car running again.
Don't risk this or worse happening to you, change them now.