Hi all, I am new to the thread. I recently bought a 2012 Jaguar XF 5.0 V8 n/a with 72K miles. I have a surging idle issue and I’m sure it has to do with the air system, most likely a leak somewhere in it. I wanted to know if anyone has upgrade the air/cooling system in this specific engine. How has it been and is it worth it? Please also let me know where I could get it, thank you all.

 

No aftermarket air filter works as well as the existing factory system. Spend your time and money on getting the idle happy.

 

well then, thanks for letting me know man! I already found that the induction noise is really apparent on this car fully stock, was honestly just trying to see if I could make it any louder. Any idea what part could be causing the air leak? Or is it best to run a full check on the entire system. Thanks

 

If you hang a pair of Magnaflows off the rear end you won’t need no induction noise. The stock mufflers are just too quiet.

Do you have a CEL? If so, start there with an Autel and see what it thinks it’s unhappy about. Hopefully it’s not cam disagree.

 

for sure, I’m going to be taking the mufflers off and putting a straight pipe through it most likely, I don’t know much about how to do it though so I will have a mechanic do it. And I also don’t have enough money for a smaller muffler and definitely not for a entirely new exhaust unfortunately.

I think by CEL and Autel your talking about code readers but correct me if I’m wrong. I’m not a DIYer, wish I was, but I’m taking the car to a euro mechanic next Wednesday and he will run smoke through the system for $65. I have gotten my valve gaskets, coolant leaks, and vacuum pump repaired by him and it’s been going good.

i still have a couple of more things I need to do to make this car perfect, it already runs well no lights on the dash but I know there’s things I can do to bring back lost horsepower, and possibly increase the gas mileage.

 

Smoke testing it sounds like a good idea. If your independent guy gets a lot of Range Rovers in his shop then you know you’re in the right spot.

CEL is check engine light. Autel is a code reader most often used by independent garages.

I had a local shop hang two Magnaflows in place of the factory mufflers. They even reused the factory tail pipe finishers. It was $650. I think straight piping it would be too loud. I tried it with my Volvo XC90 V8 and it was pretty obnoxious. What ever you do, don’t cut off the resonators.

 

If you have surging idle and especially if the car throws lean codes, check the PCV valve diaphragms. I believe the 5.0 has two of them. They can crack or split. Replacements are relatively inexpensive and if the old ones are split, that will often cure the surging idle.