Wow that bad huh, does the car operate strange? like idle rough or smell of gas being emitted from your tail pipe? n maybe you could try the basics.
-Check plugs - gaps
-Check Air Filter
-Check and make sure your brakes aren't binding on you, car aligned tire pressure up to spec ( ppl over look this )
-Check your ignition system-wires, Distributor module
-Clean injectors
-Change fuel filter
-Check and see that your exhaust system has no leaks as well.
-When last did you change transmission fluid?
-Change O2 sensor( last resort kinda thing)
-Btw what kinda engine 4G15 Dohc?
Kindly update your solution to aid others
AN YES MY ODO IN KM