Car can't finish SMOG test

I have a 1983 Ford Tempo with only 60,000 miles on it. It runs pretty well, I certainly never have any problems with it running around town. However, I tried to get it smog tested (in California) recently, and they put it on the rollers and run it at 15 miles per hour. The technician says that after about 45 seconds, the engine loses all power and deccelerates to about 9 miles per hour and can’t finish the test. (because it has to stay at 15) I have had two different locations try it two different times with the same results. The only other time I have a problem similar to this is if I drive at 60 miles per hour(or more) for more than a few minutes, the car will suddenly decellerate to 40 miles per hour (and pushing the gas pedal all the way to the floor won’t help) and then it will be able to accelerate again. Any ideas?

Ok did you mean to say you have a 1993 Tempo? There was no Tempo in 1983. I don’t live in CA but I would imagine you’d be smog exempt if the car was made in the early 80’s.

As for your power problem-when was the last time this car was tuned and the fuel filter was replaced? You could have a malfunctioning catalytic converter or a fuel problem, or in an extreme case a problem with the ignition/plugs.

If it has an O2 sensor, change it. If it has two of them, change the front one. If tht doesn’t fix it, get rid of it. If it’s a 93, it has one.

An O2 sensor has nothing to do with a significant loss of power issue.