Need 1990 GEO Prizm Help

I recently purchased a 90 GEO Prizm with 180,000 miles. The previous owner had a Japanese engine installed around 6,000 miles ago. There are two problems I'm having and would desparately appreciate any help you could give me.

1st, the radiator cooling fan runs 100% of the time, doesn't make any difference if the heater control is on defrost or any other setting. This is annoying.

2nd the car also has some sort of fuel delivery issue. I initially thought it was the fuel filter and changed it, but have seen no improvement. The car stops running at times when I come to a stop. Also at times it jerks and sputters at highway speeds. This only lasts for a fraction of a second and seems okay afterwards. When it stops running at a stop I simply start it back up again and it runs fine (until the next time it does it). Has anyone else experienced these issues, and if so how did you fix it?

Thanks Much!

Scott

Does the temp gauge read rather hot? If so, I would recommend replacing the thermostat. Don't get a Stant, I would use a Toyota part. I've used aftermarket thermostats and the engine runs considerably hotter than with OEM thermostat.

If heat guage stays around .25 off cold and the fan stays on, I would consider replacing the fan heat sensor switch (thermistor).

did you ever get this problem fixed my cousen has one doing the same thing and I would like to know if you got yours fixed and how.

Thanks
Randy

well when mine did that i had to get a new map sensor that ran me 250 bucks. after that my japan engine woke up an started kicking ass. if u guys are eintrested i will post a picture of the sensor later. as for my fan it still stays on i will find a remedy for that soon