Advice on tuning my engine

[Jan@xxxx]

Hello everyone,

I need some advice for my car: I had the Cat replaced by a pipe a 
couple of months ago (which is legal here) to get a little more 
performance out of my car.
This DID do the trick, not much, but noticable enough. The car was 
behaving beautifully when I got it back from the shop untill about 
three weeks ago. When Idling you can smell some unburned gasoline
from 
the exhausts (and no: I'm not kneeling down to notice) and I get VERY 
frequent backfires. I even get them when taking my foot off of the 
accelerator at as little as 1500rpm.
This backfiring is nice when you want to impress your 7 year old 
cousin, but that's about the only "pro" I can think of: it is not 
supposed to be this way...

If it had been this way ever since the cat was removed I would
suspect that, but all went well for at least 6 weekends of driving 
(adding up to about 500 miles). 
I also suspect my fairly poor gas-mileage to be a 
result of this: I get 6km to a liter (=1:6) (about 14mpg I think), 
while I hear of several other Dutch owners who get 10 km per liter 
(23mpg???) which is close to DOUBLE the mileage!!!
If this can't be helped so be it: it isn't my daily driver, but it 
would be nice to take a longer trip without having to refuel so often 
(except maybe for the looks I'd be missing, which you usually get
when pulling up at a gas station)...

My car is going to the shop next thursday for its' annual inspection 
and since it's going to be there anyway I'd like them to look at this 
too. This shop has had some experience with the PRV-6 in other 
configurations, including the Renault Alpine A-310, but untill I came 
along they had never worked on a DeLorean. My father happens to know 
the owner of the place which is reassuring AND they are a member of 
"BOVAG" which means they are respectable and do good work.
To make a long story short: I trust them with my car.

To make it a little easier on them I'd like to know what would be the 
first thing to look at when suffering from the described symptoms. My 
guess would be either the engine is running too rich, or the ignition 
is off. Any other suggestions are more that welcome: there's an event 
in Germany next weekend I would like to attend, but if my car's still 
in the shop then that won't really work ;-)

Thanks in advance from The Netherlands,

JAN van de Wouw
Thinking Different... Using a Mac...
Living the Dream... Driving a DeLorean...

#05141 "Dagger" since Sept. 2000

check out the Delorean-Files at:
http://www.deloreanfiles.nl/
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