Idle/wiring issue!?

1993 NISSAN SENTRA
400,000 MILES • MANUAL • ELECTRIC
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RUNGANATHAN
  • MEMBER
  • 4 POSTS
Hi so when car is warmed up the idle jumps from around 1500 revs ,when lights are off and when lights are on it jumps 1900 revs .when idle screw is adjusted lower the car doesn't idle for long then switches off and suggestions?
Jul 1, 2026 at 4:34 PM
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RUNGANATHAN
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  • 4 POSTS
Any suggestions?
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Jul 2, 2026 at 7:58 AM
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STRAILER
  • ✓ASE Certified Mechanic
  • 54,832 POSTS
  • ASE Certified Mechanic
Yep, this is a classic vacuum leak, dirty throttle body, also do you have a check engine light on? If so we need to run the codes. Here is a video on how to check for the vacuum leaks.

https://www.youtube.com/watch?v=LRKWV4Are5c

Here is a guide to help you service the throttle body which should help as well.

https://www.2carpros.com/articles/throttle-actuator-service/

Thanks for the video it helps. I would look over the engine also to check for broken vacuum hoses and a stuck PCV valve. The Positive Crankcase Ventilation Valve (PCV) is threaded into the front corner of the valve cover near the oil fill cap. Please go over these guides and get back to me.
Jul 2, 2026 at 2:03 PM
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