pls could anyone tell me why my s type tries to cut out when it's warm ( it's a 2000 w reg)

 

Sorry you need to give us much more information. It could be dozens of things!
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If it does it at idle (so, low revs and little load on the engine), it's probably an air (vacuum) leak. Search for air leak and for PCV elbow. But yes, give more info!

 

While driving? At idle? Under load/no load? Does it stumble, or just shut off? Does it (engine) actually shut off? Any warning lamps?

Provide as much info as possible if you can.

 

sorry yes it tries to cut out when it is at idle the car some times cuts out but will restart with no problem and it drives ok, also sometime's it will idle at 1500/2000 rpm i have serviced the car fitted new inlet manifold gaskets, plugs filters but no change. i have noticed a hissing sound coming from the throttle body assembly on the inlet manifold is this normal? thanks

 

p.s i used a code reader to see if anything was wrong but nothing. pps no warning lamps. no problem when cold only when at running temp

 

hissing = air leak

there should be no air leaks!

If you have a decent OBD tool, you may find either or both of:
1. it's not running CL (closed loop)
2. fuel trims (especially at idle) are well away from 0%, showing fuel being added to compensate for the extra O2 (oxygen i.e. air)
(note: unless CL, fuel trims are not meaningful and usually show as 0)

Some like to use a little propane to confirm it but if you can HEAR it then it's quite a BAD leak!

The extra revs are probably it going OL (open loop) but it will just stop doing it if you fix the leak.

 

thanks for your help i will look into that and let you know. do you think the throttle body could be faulty?

 

If you have the V6 its quite a common fault

 

If you had a vacuum leak, it would most likely have a p0171 or p0174 (or both) code stored. Same goes for a throttle fault....there would be a code, and MIL. You say you have no warning lamps or codes.

I'd put a fuel pressure gauge on it and attempt to duplicate the issue. See what FP does when the fault occurs. Just to rule out the simple stuff.

 

ok thank i'll give it a wirl and see what happens and let you know
cheers

 

A P0171 or P0174 isn't guaranteed. The hissing needs an explanation if it's not an air leak. Fuel pressure appears very rarely a problem with S-Types. Diagnose the cause of the hissing first. And if it is an air leak then fix it urgently.

 

V6 or V8?

JagV8, you are correct....there is no guarantee that a code would be stored....I would tell him to look at fuel trim , but chances are he does not have that capability. To the OP, if you can look at fuel trim, please do....and report back.