Good day everyone, I'm new to this site so bare with me. I have a 03 Jaguar S type with about 160,000 miles. The other day while driving on the highway the gearbox fault indictor came on. The car drove a little weird (it shifted a litte harder than usually but not like a hard shift) but just when I was about to get off the highway the gearbox indictor went off and the car drove fine. Now this is the second time the gearbox indictor came on, once in March and Sept. I have a check engine light since I brought the car in Feb of 2016. My observation is that the last two times the gearbox indicator came on was in March when I had a car wash and the other day going through water on the road. I guess my type of car doesn't like water. Does anybody know what may cause that?

Second I notice when my fuel is below half full the car drive horrible. For example it loses power and just drives slowly but slowing starts to get power while driving. When I make a stop (like a stop sign & or a traffic light) and pick up again loses power then I have to patiently wait as the car tries to gain power again. It takes about a minute or two for the to hit 60 miles an hour. But when my car fuel is on full tank I can race anyone I want. (haha) But the car drives normal. Why is that?

I know nothing about cars and need your help. I have changed 6 out of 8 ignition coils. But thats all that has been done. What do you guys think I should do? I love my car. It really drive well (beside those issues). Why type of maintaince should I start doing? What parts should I replace?

Oh yea one more thing, the fuel indictor meter does not work only works when I have a full tank but goes haywire when its on half a tank

 

First you need to get the fault codes read not just the p codes ,try your local parts store to see if thay have a scanner that can read all codes , and post them here ,
Also you have not specified witch engine you have ?
The codes will help point you in the right direction , with out reading the fault codes it a real guessing game !