Code reader turn off while accélérate

[MECANO]

Hi,
I have a 02 Sportage auto transmission and while accélérate my code reader send the message like i have turned the key off (err2). The engine is running well at idle but have a very poor accélération (hard to reach 60Kmh). There mil light is on and the code are P0300, P0302, P0303 and P0604.
I have checked the ground in each kick pannel and the ECM connection they were clean. I have fixed a corroded connection (single black 8 or 10 ga) under the batterie tray. After a midnight road test the problem still there. Back in the garage.
Where i should look first? Is it a known problem?
Thanks Jacques

[rjohnston79]

My code reader cuts out at times in my 2001 Sportage 5 spd, but I have not noticed a pattern.

[MECANO]

After a lots of hours of labour the problem of my 00 Sportage is finaly solve.
I have checked the fuel pressure, OK.
I replace the coils, plugs and wires, (crack in coils)
I have checked the timing belt and the key on the crankshaft, OK.
I have checked the ECM pins, B+, ign, and ground, OK
The engine won't rev. over 3500 RPM but idle well. I still have the misfire and codes P0300 P0302 P0303
I decide to remove the O2 sensor from the engine manifold.
While the engine is running i see something moving in the hole.
The first catalytic converter was broken and some pieces blocked the second catalytic converter under the car.
After i have remove all the ceramic of the converters. Now the engine run like a Swiss Watch with all is power back.
Now the only thing remaining is to purchase all these expensive parts.

Jacques