The check engine light will come on and when it is flashing it misses out, and acts like it wants to die, and smells really rich in gas. but othertimes the check engine light is on its solid it runs fine. had the catalytic convertor taken off, and it was completly hallow, is there a possibility the lineing that goes in the convertor couldbe cloging my exaust? , and if so would this cause these problems? also I have had all o2 sensors replaced. when hooked to computer it says all four spark plugs are fouled. any suggestions?