Engine Runs Irregularly, Stalls or Misfires

Content Source: 2021 RZR Pro XP and Pro XP 4 Owner’s Manual (9931538 R01) > Troubleshooting Chapter

IMPORTANT

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Engine Runs Irregularly, Stalls or Misfires

Possible Cause	Solution
Loose, missing or kinked boost reference lines	Replace boost reference lines
Loose or missing intake system sensor connections	Inspect connections, tighten or replace as needed
Fouled or defective spark plugs	Inspect, clean and/or replace spark plugs
Worn or defective spark plug wires	Your POLARIS dealer can assist.
Incorrect spark plug gap or heat range	Set gap to specs or replace plugs
Loose ignition connections	Check all connections and tighten
Water present in fuel	Replace with new fuel
Low battery voltage	Recharge battery to 12.8 VDC
Kinked or plugged fuel tank vent line or filter	Inspect and replace
Incorrect fuel	Replace with recommended fuel
Clogged air filter	Inspect and replace
Clogged intake pre-filter	Inspect and clean (with soapy water) or replace
Other mechanical failure	Your POLARIS dealer can assist.
Possible Lean Fuel Cause	Solution

Low or contaminated fuel	Add or change fuel, clean the fuel system
Low octane fuel	Replace with recommended fuel
Clogged fuel filter	Your POLARIS dealer can assist.
Low fuel pressure	Your POLARIS dealer can assist.
Loose, missing, torn or kinked boost reference line from manifold to fuel pressure regulator or blow-off valve	Replace boost reference line