RPM Fluctuations in Khyber After EFI Swap — Could It Be a Sensor Issue?

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RPM Fluctuations in Khyber After EFI Swap — Could It Be a Sensor Issue?

My Khyber’s RPM goes up and down randomly, especially while idling o r in traffic. I’ve already cleaned the throttle body. Some people told me this could be due to a faulty TPS o r IAC sensor. Is that true for Khyber EFI swaps, and how do I properly diagnose it?

Gari Specialist asked on 16 Apr 2025 12:51:56 pm

1 Answer

13 views |

Gari Master - on 16 Apr 2025 12:53:55 pm

RPM surging high and low fluctuation is a classic EFI problem when certain sensors o r calibration steps are skipped.

Most Likely Culprits:
TPS Throttle Position Sensor: If the TPS is not calibrated properly, the ECU may keep trying to adjust idle, causing RPM fluctuations.

IAC Valve: A dirty o r malfunctioning IAC will fail to manage airflow at idle, leading to unstable RPMs.

Vacuum Leaks: If the intake has a small air leak, it can confuse the sensors and cause idle surges.

Grounding Issues: Poor electrical grounding can cause inconsistent signals to sensors like TPS o r IAC.

Fix:
Recalibrate the TPS using a multimeter. Voltage at idle should be around 0.5V, increasing smoothly with throttle.

Clean o r replace the IAC valve.

Check vacuum lines for cracks o r disconnections.

Add extra ground wires to the engine block and ECU body.