I have a Ford Focus that we put an enigne in about a year in a half ago. About six months ago I had an issue with my od off light coming on and not going back off even when pushing the button took it to a mechanic and he fixed it. After that about a month later my car started to sputter. Only at certain speeds and was starting to get worse so since we had a similar problem on a neon about a year before and found that the problem was fixed when we fixed the sparking of the spark plug wires we tried that first with the replacement of plugs and wires. This fixed the problem til just recently. A couple days ago we were having a problem with a back wheel cylinder and had to take it off to replace. After replaced and took it for a test drive we found that the od off light comes on and off, a lot of sputtering, dogging down of the engine, misfires, a burning smell of some sort and then a strong fuel smell came about. When parked you can hear the sputtering and a strong sulfur smell through the tailpipe. Any suggestions greatly appreciated since this is the greatly needed transportation for the one who is not laid off through this economic difficulty. We can not afford a shop. Thank you!