1. If the battery is the original I would replace it otherwise check the
water level in it and charge it overnight with a trickle charger at the 2
amp setting.
2. Test your starter and solenoid. Let a garage do this or buy a copy of
Haynes repair manual ($20 cdn) and do it yourself.
3. Clean out the inside of the throttle body. It gets gummed up and may be
blocking air. See my procedure under the NISSAN category under 'gas pedal
sticking'.
4. When was the last time you changed the sparks plugs, wiring and
distributor on that baby?