After so many years dealing with cars (owned a foreign used car dealership for 25 years) I've become accustomed to unfamiliar noises, creaks, and any unusual characteristics for a car I'm familiar with. During the last 3 months or so, I've noticed what I would call a "stumble" in the engine that might last a fraction of a second. It only happened 3 times and always when I was standing still at a light in drive. At first I didn't give it any thought, but after experiencing it a few days ago, I got to thinking it was possibly a weak ignition coil, fuel pump, or some other hiccup that would probably be more trouble than it was worth to look into as it was so infrequent. Of course my concern was if this is an issue that might progress. Have any other members experienced the same or something similar? My car had 2 recalls, both of which were supposedly done, one involving a software update to fix a fuel pump issue. Any thoughts? Should I be concerned? Car runs perfectly in every other respect with 20,000 miles. I'm sure most drivers would not even have noticed the very faint "shake" that could almost be mistaken for a moment of bad gas that lasted a fraction of a second.. Thanks all.

 

Seems to be at a different time, but does sound like what I call my shimmy.
Mine is once when I start it and once when it settles to low idle. But never just sitting at a light once warmed up.
My indie guy said for me it was most likely the motor mounts.

but after warmup it almost sounds like a misfire of sorts like you suspect.

 

I stopped by Jaguar today and told my service writer about the symptoms (who was the Jaguar shop foreman originally). He said it's possibly an injector or an ignition coil. Recommended 2 bottles of techron on a full tank of gas and run it down to 1/4 of a tank. Certainly worth a try.

 

Sorry I was not able to correct the title of this thread to SLIGHT STUMBLE WHEN IDLING IN DRIVE

 

Just filled my tank, so also just ordered 2 bottles from Amazon.
Only adding one 12oz bottle, but figure it couldn’t hurt at 83k miles.

 

The previous shop foreman suggested 2 bottles as the 18.5 gallon tank would handle it. He mentioned an earlier model (with direct injection like our XK but don't remember which model) had a similar problem of which JAGAUAR recommended the adding of Techron. He's been with Jaguar for a Zillion years and mentioned, the techron actually resolved the problem. I'm planning on getting two bottles tomorrow and giving it a try.... nothing to lose!!! Always try with the small stuff first..... Besides, pulling the injectors or ignition coils on our cars is a BITCH!......I wasn't going to do it anyway! lol

 

Techron technique worked for me originally on a 1986 Cadillac, and I have sworn by it ever since. In fact, the only fuel I use is Chevron, or some Texaco stations carry it with the Techron additive.

 

Local Autozone has Techron complete $11.99 buy one get one free!

 

. That’s a very good price especially if they are 12oz each. I picked up 2 at Walmart for $8.38 each but were 10 oz. I’ve always had good luck with Techron and I basically only use Chevron anyway with Techron added.

 

Aged injector coils and aged spark plugs are a known culprit for this situation.

 

Yes true. But with 20,000 miles I thought I’d give the Techron a try.