So i love my 01 S-type and i treat her.. yes its a female lol , like a baby. Recently i started noticing that the car has been hesitating when idling after start or when I'm not in motion. Ive looked up the information and have done my homework from jag repair.com and i wanted to ask you guys as a community if theres something that your seeing that i may have overlooked. The car has 168K miles on it and its a v8 4.0 . i have attached my obd codes below as reference, any help will be much appreciated , don't want to sound like a noob that doesn't search .

 

P0125 - probably stuck open t-stat. Does the temp gauge take a long time to get to the middle?

P0153 - O2 sensor likely on its way out. I would try switching the two upstream sensors and see if the code switches to the other bank. Or just get a new sensor, preferably OEM.

P0301 - Likely a bad coil pack. Again, switch it to another cylinder and see if the code follows it, or replace the coil pack. Wouldn't hurt to check the spark plugs while the coil is off, too.

P0442 - Likely a loose fuel cap or bad seal at the filler neck. This will be tricky to find without a smoke tester, as the leak may be anywhere. Sometimes they are near the evap canister or the rubber lines under the hood get micro cracks.