Nissan Repair: Nissan 300ZX Twin Turbo engine dies when decelerating, nissan 300zx, 300zx twin turbo engine

Question
Hi Von,
I have a 1991 Nissan 300ZX Twin Turbo with about 105K miles.  The car works just fine until I degrease the engine over the weekend.  Now, the car dies every time I slow down.  The following lights are also on: HI-CAS, high beam, parking brake, seatbelt, even when i restart the engine and accelerate.  These lights do come on during normal starting but go off after a few seconds.
Prior to degreasing the engine, the engine also dies but only slow down from a highway speed, and only when the weather is about 80F.  Works fine if the weather is hotter or colder.  Now, it dies every time i slow down regardless from what speed.  Please advice where should i start checking?  Thanks.

Answer
Matt,

I would first get the battery charged and then go to Autozone or Checker and get the electrical system inspected.  It sounds like the alternator from first glance.  Also, you are probably looking at getting the master headlight switch, the one on the column, replaced to correct the high beam problem.  Nissan uses contacts in the headlight switch and it sounds like yours is stuck.  If not, then it is the high beam relay.  But, with the year it is most probably the switch.  I would check the idle air control valve and clean the throttle bodies.  You might just replace the idle air control valve due to the age and that, along with the cleaning should take care of the idle problem.  The HI-CAS is probably the center switch.  Email me back if you need more.