When we bought this car 2.5 months ago there was water down in the holes where the coil packs attach to the spark plugs. We soaked up as much water as we could, removed the coil packs, and cleaned out the remaining water. Cleaned out the coil pack plugs. And when we removed the spark plugs there was no water, and very little burn on a couple of the plugs. Got new spark plugs, put everything back together.
Fast forward to this week.
Driving the car, and suddenly we get "restricted performance" notification while accelerating up an onramp.
Then today, car runs fine until it gets around 3000 rpm (red line is 6800)
​​​​ then it started cutting out/surging. Moderate acceleration up to 2500 rpm is fine. Normal driving is good, and it will travel at 75mph with no issues.
but no full throttle. You have to ease into it.

I began doing a search on here for the restricted performance issue, and saw I should start with the fuel filter, which I will. We will also yet a diagnostic ran, but it will only be from a chain auto parts store.. nearest Jag dealer is over 120 miles away, so I'm not sure if it will be able to tell me if there's an issue with the fuel mixture, but we shall see.

Finally, I come back full circle to the beginning of my post.
I saw another Jag owner with restricted performance, and he said there was water in the coil pack/spark plug holes!!
So I'm wondering if that's my issue again. The problem is, I can't fathom a source of the water??
​​​​​​​Any thoughts?
​​​

 

I'm guessing TB pos sensors? Just throwing that out by how it happens at the midrange. If it was an XJR I'd say secondary pump but your VDP only has one.

Water in the plug holes could be caused by poor storage conditions and bad seals around the coil pack covers maybe? Even then it's a very difficult angle for water to just drip into while sitting.

Try taking off the coil pack covers and pulling a coil out, should tell you if there's water in there again. Post any OBD codes the store pulls and that will give more of a direction for advice.

 

For codes, if your using a smart phone, the ELM 327 OBDII Bluetooth unit seems to be a site favorite. If not, you can buy a handheld most anywhere.
Here's a link for review from the Tech section... https://www.jaguarforums.com/forum/g...-%2A%2A-33347/
As for the source of water, you have to ask, is it just water or is there coolant mixed with it? ...can you verify that for us? That being said, check your seal along your coil/plug cover. If by chance you have seepage and condensation build up, it should be there in the cool morning. So I would check under the cover for moisture in the AM before running the motor. Is the car garaged or kept outside?

 

Since you bought it recently i would vemture to say the engine bay was washed, a hense your source of water. But then again we both know about how it rains in texas.

 

Been having this problem with my '99 VDP as well. Was throwing coil pack codes and when inspected, there was found to be water in the spark plug holes as well. I've since replaced all of the coils, but this has failed to remedy the problem. Saw someone suggest earlier in this thread that I should inspect for possible coolant leakage as well. That will be my next step.

 

I have no idea if my experience applies, but for what it is worth:
I recently removed the cam covers on my '99 XJ8 to check the secondary timing chain tensioners (3rd generation - whew!) and replace the gaskets. While at it, I replaced the spark plugs and cleaned-up all the coil packs and the rubber boots that seal over the top of the plugs (they were slightly oily from seal leakage). I laid the parts out on a towel on the floor of my basement garage overnight. The next day, there were beads of water on all the rubber coil boots, but no other parts. The weather had already turned hot and humid here in Georgia, and my basement garage is dug in rock and dirt on 3 sides, with thick poured concrete walls. The basement stays cool during the day and cools down even more after sundown. I surmised that condensation of humidity had occurred on the boots overnight. I have no idea why only the boots were wet. I wonder if humidity and temperature changes resulting in condensation could be your problem? Over time it would seem that this might build-up water deposits in the plug wells. Just a thought. Probably not applicable, but there you go.

 

That is a very interesting thought.
And I'm fact, I bought the car near Phoenix, AZ, and trailered it home to south Texas. Quite a change in elevation and humidity.

 

I checked this morning and there was no water in the holes. So, I'm gonna assume the issue is resolved, and has to do with either the seller washing the engine before I bought it, or condensation changing altitudes and temperatures.

I did go get the dx ran and have some codes... should I post them here or start a new post to list them?

 

I think it would be best to post here to keep the story together.

 

+1, like RJ237 says, keep it together.