Been searching around for a few days, time to post. A few days ago i replaced the left side hydraulic motor mount on my 01 focus and since the engine has been running horribly. At first it seemed like just a low idle, but the motor has no power when driving, has died on several occasions and is still running horrible. After driving it for an hour the CEL came on so i scanned it, came up with p0135 and p0141 o2 sensor heater circuit. The only thing i can think of is that we may have disconnected a ground that may have been under the motor mount. What im looking for is where any important ground wires are on that side of the motor and what else may have gone wrong. At the time the throttle was sticking in WOT position so i used some MAF cleaner on the spring on the side of the TB and two small sprays on the butterfly to clean the edges of it. My brother told me that an o2 sensor problem shouldnt make it run rough and die but it would probably be a vacuum leak. Any help is much appreciated, BTW i like what you guys have done with the forum; looks great.