Nissan Repair: n12 pulsar afm, tps, air con in reverse, neutral safety switch, volt ohm meter

Question
Hi there Von, I have an n12 pulsar vector ti 1.8 auto.
The ecm light comes on and off, and when checked for faults, came up with tps and afm fault. It sometimes jerks when over 65kph if you have the accelerator steady, but is smooth if flat. Also after car has been stopped for short period, when taking off from 0kph it will cut out at a couple of thous rpm until I back off the accelerator, then is ok. When I bought the car, the man said he had the tps replaced. The strange thing is, when I put the car in reverse, it turns on the air-con, whether the button is pushed on or not. Does this sound familiar? Can you please help? Thanks Russell

Answer
Russell,

The codes would indicate that the throttle position switch and the AFM are setting codes.  I would check the wiring and connectors before the purchase of new ones.  Also, the airconditioner coming on in reverse tells me that there is something going on with the wiring.  Probably the relay box is where someone tied into the harness or bridged a relay or two.  There is no reason for the airconditioner to come on when in reverse.  So, I would check the relay box first and then the neutral safety switch where the reverse switch connects.  Get a Haynes Manual and check the TPS for proper voltage at the idle setting.  You will need a volt/ohm meter and both the meter and the book cost about $20 bucks each.