emm, couples of points to check:
- how many load you have on car (how many ppl)?
- which brand petrol u using? (not sure only me or wat, Shell is having bad FC on my cars)
- when do top overhaul, got change piston ring?  got check the ring to cylinder wall clearance? would it be cylinder wall wear off or piston ring wear off causing bad compression rate?
- try full service or overhaul the carburetor. This is the thing i hate most of my wira 1995 auto (besides the 3-speed auto tranny).
- tyre pressure okay? >210 psi?
- tyre alignment okay?
- try don't put any useless stuff/load on the car (like heavy stuff which u dun use everyday)
- do u idling a lot (like waiting for ppl, besides the usual traffic jam)?
- aircond compressor working okay?  it got drag the engine or not...

my car is having as bad FC as urs too, even after full overhaul. Same year car, but it's auto. I am driving less than 10km/day, and i step on the accelerator and brake like siao lang, so expected the bad FC.

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Added on April 30, 2011, 2:34 pm

Should say W5W...
can refer to here --> http://www.lighting.philips.com/in_en/cons...ighting&lang=en

yours a carburetor type? if so, your carb could be problem.

carb setting could be problem.. the carb itself could be 'dying'.. time to change the carb, perhaps?
im a GSRian. 
1) good engine, spareparts easy to get. overtake car without downshift.  , FC better than my 1.5I auto.
2) a bit more than NA. i change engine oil at 3k++, mineral only.
3) engine PNP, no modification needed. JPJ approved.
4) no. since you're ready to do transplant, i would suggest to go for the turbo. for once, try it, and you'll love driving. 

it was 2++yrs ago. rm13k OTR.
with std GSR engine, i believe the chassis is strong enough to handle the power.
your car accident b4? to wat extend?

Wira got 2 fans, 1 for aircond and 1 for engine. maybe the engine fan didn't work thats why even when temperature high the fan didn't spins to cool it down.

SP is? I tried 2 Manual Wira SE 2005.

1 completely no sound when i drive (5k more expensive)
another 1, i can listen the engine sound clearly inside the car.

Guys, how much does it normally cost to change power steering fluid?and is it necessary?the mehanic is asking me to change since its already black and got debris..charging rm150..

So many things to change pokai already..regular service + spark plugs + brake fluid + steering fluid + tayar gonna botak T_T

rm500-700 better just change the speakers and call it the day.... With such amount of money, nothing much can be done except make the sound worst....