P38 MPG Issue on 4.6 V8 Autobiography

Having trawled through most of the MPG threads on here and checked or replaced most of the parts that could be linked.

Im getting around 13-14MPG on a long run doing a constant 60-65 mph. Im assuming from what i have read i should be getting at least 18-20 when im on a run is this correct?

Round town im getting between 10-12mpg this is ok by what i have read im assuming?

Since changing the cats the MPG has gone up froma constant 9mpg to the above so that was one of the problems obviously.

I have changed the cats for new ones as the old ones had broken up.
The lambdas are original (but it breased an MOT emissions test)
MAF is working.
New Plugs and leads
Oil Change / service

Is there anything else you guys could sugest? Or know of anyone in the Essex area with a Test Book or recommend a good indi with diagnostic equipment.

Thanks

Andy

wooo i never got more than about 12 on my 4.0.

live with it.

12.5 from my 3.9, never did any better

mine does... according to the mess center around 10-14 round town and 20-22 on the m'way

I only get around 20 MPG around town in my 1998 2.5 DSE, so yours does not sound to bad to me.


firstthebanker

Fair enough, i just herd that they do 18-20 mpg on a long m-way run.. Thought there was something really wrong with it seeing as i cant get it to go over 15 mpg no matter how i drive.

Well thats reassuring to know that i have now fixed the problem by changing the cats over.

I might still try and get it on a test book to make sure nothing else is wrong with it apart from what i know. A/C condenser has a pin hole in it so A/C isnt working and the sunroof isnt set.

Apart from that shes working fine now then

buy a diesel and chip it, i get about 26-28 round town and i got on way down to kent from northampton a whopping 35. dont think id ever get a v8 with these figures and i dont think its far off performance either since being chipped

swwrob said:

buy a diesel and chip it, i get about 26-28 round town and i got on way down to kent from northampton a whopping 35. dont think id ever get a v8 with these figures and i dont think its far off performance either since being chipped

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i agree,my p38 diesel has the psi powerbox fitted and the mpg is very good,the performance is not to shabby either.

i have a 2000 4.6 v8 and round town i get around 14-15 mpg and on a run if i keep below 70mph about 20-22mpg but if i go over this will drop to around 18-19mpg thinking about getting rid and getting a audi A4 tdi

gemsdad said:

i agree,my p38 diesel has the psi powerbox fitted and the mpg is very good,the performance is not to shabby either.

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how do you know, its been abandened on the drive!!!:doh::doh::doh:

swwrob said:

buy a diesel and chip it, i get about 26-28 round town and i got on way down to kent from northampton a whopping 35. dont think id ever get a v8 with these figures and i dont think its far off performance either since being chipped

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I bet those are not brim to brim figures. The message centre average MPG is way off when the vehicle has been chipped, over reading by between 2 & 5mpg according to how you drive.

swwrob, what chip do u have??