Your car is stumbling on accel and gives a rotten egg smell you changed the plugs and coils what to do next and how would you go about changing the cat converters?

Answer 1

Again, first change the oxygen (O2) sensors. The O2 sensors are what regulates the gas/air mixture. Improper mixture will cause the 'rotten egg' smell. As far as changing the converters, assuming this is a Lincoln Mark VIII..., it is not easy. The left converter and exhaust manifold is a 'one piece' construction. It is also 'wrapped' around the steering rod. It is real hard to remove. One way to more easily remove the converter is to use a torch to cut the pipe between the manifold and the converter. You will need to remove the O2 sensor to keep it safe from damage and you will need to use a 'heat sheild' between area to be cut (and then welded) and the bottom of the vehicle to lessen the chance of heating up the carpet enough to catch fire. The composition and position of the cut area makes it difficult, but it can be cut and then welded back together. I suggest a 'Tig' or 'Mig' welder be used.

The catalyst sits in the exhaust system and can be easily removed. It just fits in like any other exhaust section. The rotten egg smell is indeed the cat breaking down but this might be a symptom rather than the cause. If the car is stumbling then its not burning all the fuel properly and this raw unburnt fuel is passing into the exhaust system which in turn is disolving the cat. If the car is only running on 3 cyls (on 4 cyl eng) try and narrow down the cylinder not firing by removing injector plugs one at a time until you find the one that doesnt drop the engine revs any further when disconnected. Then you can trace the fault back on that circuit. If you need to drive the car to a garage , disconnect the injector plug from offending cyl and this will stop the fuel damaging the cat.