Thread: economy, dead spot, sparkplugs

Just thought I would share my recent experience with my P38

For a while I have been having bad economy when towing my 21ft caravan
and when under load such as towing uphill had a massive dead spot as in no power between 3500-4500 rpms

I also recently had my P38 on a 4WD dyno and saw that not only was I missing a third of the
horses that I should have but a bloody v6 Toyota had more than me

so it was time for me to play bush mechanic

As well as dead spot my P38 also had slight hesitation at 4000rpm
at times when accelerating from 100kmph I would hear pinging and I felt economy
was to good at 14.5 avg/l per 100km
I suspected that it was sucking air after the MAF sensor, needed spark plugs
or had a faulty MAF sensor

Air system looked Ok so I pulled my plugs and found that the best plug had a 2mm gap some were closer to 3mm

standard plugs on the p38 are champion platinum I wanted the same as they are a known
quantity and the ones I had lasted well past that expected 100,000
but no one had champion
bosh info kept leading to old school type plugs (clearly wrong)
so I went NGK

thus far I am very happy the massive dead spot from 3500-3500 revs has gone and my highway economy is unbelievable
@100kmph can hit 10.1 avg/l per 100km with average of 12.4
@80kmph average 10.4

I have regained missing horses then some but
I occasionally still hear pinging and a barely noticeable slight hesitation @4000 rpm
so In considering this with economy I suspect a new MAF may be in order they are meant to be replaced at 60,000
my car as done twice that and as plugs were factory I'm sure the MAF is factory to

regards Peter

YEP cleaning works... as per what the other guys have said, but I bought MAF cleaner from dick smith. About $15 a can and I give mine a (gentle) blast at every service 5-10,000 km's.