Hello all,
My Jag started shaking when idling last week and then got the limited performance and engine light error. So, I replaced engine oil and PCV valve but it didn't solve the issue. I took my car to the repair shop where they replaced one ignition coil and spark plugs but still it didn't solve the issue (rough idling and smoke). Now they are suggesting me to perform an engine cleaning procedure to remove any build up on piston and other engine areas, but the chances of solving issue are less than 50%.
Does anyone have such issues or any suggestions? How about changing the head gasket? I am hoping that my car will survive and don't want to scrap it!
Thanks.

 

You need to pull codes, otherwise you are just taking a stab in the dark. The codes will tell you where to focus. You can get cheap code readers off Amazon and eBay, or search these forums for more expensive readers that will give you access to certain additional Jaguar systems (e.g., I use an icarsoft 930 which allows me to read things like transmission temperature, I can use it to reset ABS codes, etc.). You can also use the real time data feeds of a code reader to gain some insights as to the issue. For example, if your fuel trims are pegged to the max, then you have strong evidence of a vacuum leak and then can start finding the vacuum leak.

As for head gaskets, that job I would view as a last resort and I would undertake it only if it has been verified to be the issue. Head gasket swaps are very labor intensive (I would guess $5k or higher). Good luck with it.

 

If the shop you took your car to did not pull the codes before telling you how bad everything was, how did they know which coil to replace? I am really surprised any shop nowadays would not have a code reader. Have you used this shop before? I have only had the injection system cleaned on one car in my entire life and that was a warranty job many years ago. It may have helped but I could not swear to it. I only went for it because it was "a no cost to me thing" and my car was actually running well at the time anyway. That procedure is not used as much as it once was. Gasoline is much better compared to 10 - 15+ years ago. If you stay away from the really cheap places for fuel anyway. The "top tire" fuel has additives that help keep the injection system clean. There are a great many other things that should have happened before a head gasket went bad. Did you have any other issues/symptoms? Most parts places like AutoZone will read your codes for free, at least the power train (engine) codes.

 

I just got my car back! Yes, I used this repair shop before and they specialize in import cars.

They are saying that it is better to clean piston rings by using a special cleaner and use 5W-40 or 10W-30 instead of 5W-30 along with the oil saver additive. The car is working a lot better and they want me to try different things to see anything helps where there might be a stuck piston ring. Obviously, they wanted to charge me a lot of money to do this so I deceide to try myself. Have you tried any fluids/ additive to solve this issue?

Thanks.

 

time for a different shop because they sound full of it. You would not just all of a sudden have a stuck piston ring. And if you did, you could diagnose that with compression and leakdown tests.

steps for shop
1. Read codes and tell them to you
2. Look at all the spark plugs for signs of an issue in any cylinders
3. consider any deferred maintenance that may be needed (new spark plugs for one)
4. All this should have narrowed down the issue substantially to the point where it may be time to buy some parts.