Mitsubishi Repair: jerking around, mitsubishi eclipse, faulty computer

Question
yes i have a 1990 mitsubishi eclipse 1.8 liter no turbo. the other day i was driving home from work when on the highway i put it in 4th gear and the car started jerking as if i was repeatedly tapping on the gas but i had the gas held steady. i thought maybe i was out of gas but i just filled up that morning if you have a suggestion or an awnser that would be great please help.

Answer
Kevin,
When you're driving at highway speeds (assuming 55+ mph) and you drop it into 4th, your RPMs would probably jump to between 3500-4000 RPMs.  With higher RPMs, your car will use up more fuel, and there will be a larger strain on your fuel pump.  You should have fuel system checked for clogs (replace your fuel filter) and make sure your fuel pump is operating properly.

Also, you should check your intake system for any clogs.  If your air filter is real dirty, this can cause the problem you're experiencing.  Replace your filter if it's been over 20,000 since you last replaced it.  Your EGR valve should be inspected and cleaned, as well as your throttle body.  Replace your PCV valve too.

It's also a good idea to inspect your car's computer.  Read this article for futher information:
http://90gsx.com/eclipse/cap/caps.htm

If your ECU is malfunctioning, you can have all sorts of strange problems. Take a look at it to make sure it's ok.  A faulty computer might think your timing is off or cause fuel-cut with a sudden increase of RPMs
Good luck!