Nissan Repair: High revs Nissan Pulsar, air control valve, nissan pulsar

Question
My daughter has a Nissan Pulsar Q about 1990.  Sometimes her car is hard to start and idles rough, other times the revs soar and she needs to brake to stay in the speed limit. The throttle is not moving when the revs climb.  This is an intermittent problem.  A mechanic recently put in a new 'computer', but this did not fix the problem.  Any ideas please??

Answer
Peter,

Sounds like the idle air control valve is sticking as are the injectors.  I would perform a tuneup first and then replace the fuel filter and put in Lucas injector cleaner.  The tuneup will consist of plugs, wires, cap and rotor.  If the tuneup has already been done, do the injector cleaning, filter and be sure to check the MAP sensor to make sure it is not plugged up.