Auto Parts: toyota corona gas consumption, spark plug wires, toyota corona

Question
Hi,

I have a '93 corona M/T, I was doing 8-10 km/liter of
gasoline last year.
I was wondering if why it is doing about 4-5km/ liter today.
Aside from that it idles erractically.

So far here are the repairs that was conducted to the unit:

it was in the paint shop for almost 2 months
2 months ago- change oil
3 months ago- top overhaul
5 months ago- tuneup

Can I ask for your advice on this matter?
Thanks

Answer
    Tuneup means just the ignition parts, I assume.  Top overhaul means a valve job, also an assumption.  Even if done poorly, the result should not be doubling fuel consumption.  I do wonder, though, since the valve job was done after the tune-up, if a spark plug could have been damaged or two spark plug wires fitted to the wrong cylinders.  This would produce a bad idle and cause the engine to run on two cylinders, halving the fuel mileage.  So, check those first.

    Body shops are like sinkholes of bad karma for most cars.  Something untoward always happens to a car that spends more than a day or two in one.  You will need to check that all fuel lines and any electrical connectors are intact and correctly routed.  This is the sort of thing that usually happens in a body shop.  Also replace the fuel filter and run some injector cleaner through the fuel system.  Other than this I can't really think of anything else to try, aside from a visit to the Toyota dealer's garage.