@needz
There are number of factors involved:
Generally mechanics are not familiar with EFi engines. They use their old experiences and try to apply the same rules for EFi. After hit and trial, the owner gets frustrated and then they try to seek solution for their problems here and there. Daewoo Fan Club is one of the platform to discuss such issues.
The car is now too old and after such a long period (around 17 years), the car needs complete refurbishment. People usually ignore smaller problems and after passage of time, when the problem gets out of control, they get their cars to workshops.
People should think about:
a. Replacing atleast all the Sensors in case of Fuel Injected cars. All the sensors have specific life (~7-8 years) after which they give erroneous readings to ECM. For example the severity can be damaged gaskits due to malfunctioning Coolant Sensor 
b. Connectors are the most important part for and EFi engine. It is suggested that the connectors be cleaned after every 2 years. Usually WD-40 is sprayed and rinsed and this cycle should be repeated thrice.
c. Get the brakes serviced every three months.
c. Regular and Timely routine maintenance is very important
d. Get wheel alignment checked at-least every year
e. Suspension parts should be replaced all at once upon detection of atleast one worn-out part. Since one part is worn-out, sooner or later other parts will also needing replacement.
f. Replace/Rebuild Engine using genuine replacement parts. Water pumps + Oil pumps are one necessary item to be replaced. Mechanics usually tell you that these parts can are fine, but it is strongly recommended to replace them, as these parts can cause engine problems in near future.
- Initially Daewoo was one of it's kind in Pakistan. Mechanics at that time were totally unfamiliar with the "Computer" system so they created a mind set about this car that is very difficult to work on. That thing still exists, mechanics are reluctant to put their hands on Daewoo :(.
