I have a 93 Evo 1 that ran fine for 6 months then start to consume double the fuel and also idles roughly and in the lower rpms the engine shakes and there was a lack of power as well. During this time I also went through 2 fuel pumps does anyone know what might have caused this????

I am also thinking of replacing the oem fuel pump with a walbro 255lph but I am not sure if this would work on a stock Evo. Would the walbro work as a replacement to the oem fuel pump?

 

sounds like you know little about cars.
i would recommend taking it to a local garage, someone you trust, and get them to look it over.
knowledge is power, but a little knowledge is dangerous

 

OK so to get more detail on the issues here is what is happening with the car. It has a rough idle, at lower rpms when pushing on the accelerator the engine shake a lot, loss of power, fuel mileage went from 400km/tank to 200km/tank, black puffs of smoke come out of exhaust, the warning light on the dash to signal the cat is running hot comes on all the time, and car is hard to start when it gets really cold although most cars don't start all that well considering how cold it gets here

So far I have replaced the following items:

Engine rebuild
Spark plugs
Spark plug wires
Coil pack and igniter
Fuel Pump
Fuel Pump relay
ECU
O2 sensor
Cam Angle Sensor
MAF

Any other ideas???

 

I'll offer this idea since you've tried everything else. My car started acting the same way. I replaced the fuel pump, fuel filter, plugs, etc. No luck. Drove me crazy. Turned out that the gas station I used all the time was getting water into its tank. I had been going there for years with no problem, so I never considered that might be the source. I switched to a different gas station, and the problem went away.

 

Have you tried swapping out the cat? You said it's running hot according to the dash and that would cause some of the symptoms you are having. I would just throw a test pipe on there and call it a day, if you can get away with it that is.