Meouch, you only need the one filter. As for the secondary filter, my car does not have that second filter. if you can, take a picture of what you are talking about. All you should have in your intake is the air filter, then a MAF sensor, then the throttlebody. Sure you are going to have a few lines coming off the side to provide the low vacuum lines for various pieces, but that is trival in the big scheme of things.

 

maybe there's no filter in there - but isn't there a box attached to the oe filter box? and it's attached to the oe intake hose after the maf sensor?

 

ok - there are two holes in the corrugated tube going to the throttle body - small one for vacuum and a bigger one - what's the bigger one for?

 

This problem seems to be contagious. My 2001 XK8 has exactly the same problem as aCapiz and was just noticed while touring in the mountains of Vermont. At first I thought it was just a rumble due to road conditions while accelerating up the mountains but it seems to have gotten worse. Interested in seeing if anyone finds the problem. In the meantime I will give it a dose of injector cleaner.

 

 

That's a resonance box, it only has a connection the the air intake.

 

 

Deep Thought

 

Greetings, iownme,
Thanks for your informative posts, which for the most part are well beyond the pale of my understanding and mechanical capacity. I have this terrible stuttering issue between 1000-2000 RPM, and often down-shift to get RPM's up and stop the stuttering/hesitation. This post is titled "hesitation when accelerating - RESOLVED," yet I could not find a clear resolution. My mechanic said it was a 'fuel issue'; old Jags not designed for new fuels with ethanol, etc. Basically, he brushed me off. His answer VERY unsatisfactory. As a frequent contributor to this forum, can you kindly shed some DEFINITIVE light on this issue? I want to give the car to my son, but can't while it runs like this. Finally, I only just joined this Forum and have NO idea of rules and regs, but can I Venmo you $25 for your insight, please? Thanks, Miguel

 

Iownme left this forum after years of helpful contributions because of a mod. The best advice I can give you is use the SEARCH function and read, read, read and then read some more. NEARLY everything that has happened to an X Type has been discussed more than once here. The years of posts are a great source for research.

 

I


i also want to know. It’s very annoying. Does it right at same point and odd slower times if o give it gas

 

I have the hesitation on acceleration problem on my 2004 type x. Haven't seen a satisfactory one fix answer. Maybe there is not one but here's the weird thing. Took me awhile to notice that car runs like a rocket when tank on near empty. No hesitation ever. Could fuel pump be getting too cold in winter?

 

Assuming you have a 2.5 or 3.0 petrol V6, the fuel pumps can become intermittent but that doesn't generally manifest itself to low fuel pressure, normally will be a complete cut out of fuel delivery at various times.
If you have noticed the tank level is a factor, perhaps you are developing a higher level of vacuum in the fuel tank which could be making fuel delivery more difficult.
Perhaps try momentarily releasing the gas cap when you are experiencing the issue to see if the symptoms go away briefly.
Because these cars have no fuel return system, their fuel management and evap systems are quite complex and you might have a fault that is creating too much vacuum in the tank.

 

I filled the tank 3/4 and the hesitation immediately returned. I removed the cap and it immediately went away. Now what?

 

Start with the easy things.......You might be over tightening the gas cap....golden rule is to only do it up to "three clicks". Over tightening it has been known to cause some issues.
The gas cap might be faulty and allowing too much vacuum to build in the tank.

When the car is started it applies some intake vacuum through the Evap systems to draw any excess tank fumes away from the tank and charcoal filter system. If there is a fault in the evaporation system you would normally get some related error codes if you connect a suitable OBD11 scanner tool.

Start with checking gas cap before you think about going any further with looking for any Evap system oddities.

 

I posted a similar thread years back. I never found the solution, however I did notice that having the AC on - regardless of cabin temp, just having it pressed on - puts a noticeable draw on the acceleration and engine response. The minute I would turn AC off the car was really zippy and responsive. I only noticed when my compressor went out in the fall 2yrs ago and I waited a few months to replace it. I was used to how the car had been peppy and responsive, but when the compression was replaced there was a noticeable lag in response all of a sudden just like I had remembered. Could be the cause. I recently replaced my fuel filter and the lag with AC on isnt as bad. It’s not as bad when it’s cold out either.