Why Your Nissan 350Z Stalls or Idles Rough After Filling Up With Gas
Is Your Z Acting Up at the Gas Pump?
There is nothing more embarrassing than filling up your sports car, only for it to sputter, choke, and nearly die the moment you try to leave the gas station.
The Short Answer (TL;DR)
If your Nissan 350Z (Z33) idles roughly, stumbles, or stalls immediately after filling the gas tank, the culprit is almost always a stuck-open EVAP Purge Solenoid Valve. This allows excess fuel vapors to flood the engine intake, causing an overly rich mixture. The fix is replacing the purge valve with a genuine OEM Nissan or Hitachi unit, as aftermarket versions frequently fail out of the box.
The Community Question
A 2006 Nissan 350Z owner reported a frustrating cycle of issues. Initially chasing a "hard to fill" gas tank problem (where the pump constantly clicks off), they replaced several EVAP components.
However, after installing a budget-friendly EVAP Purge Valve from an auto parts warehouse, the car developed a new symptom: severe rough idling immediately after refueling. The car would smooth out after driving a few miles, but the Check Engine Light (P0443) persisted. This pointed directly to a failure in the evaporative emissions control system.
The Mechanical Diagnosis: Why This Happens
The EVAP system is designed to trap fuel vapors in a charcoal canister so they aren't released into the atmosphere. Under specific driving conditions, the Purge Control Solenoid Valve opens to allow the engine vacuum to suck these vapors into the intake manifold to be burned off.
When you fill your gas tank, the fuel displaces a massive amount of vapor. If your Purge Valve is stuck in the open position (a common failure mode for cheap aftermarket parts), those displaced vapors are forced directly into the engine intake while the car is idling or starting.
This unmetered flood of fuel vapor creates an extremely "rich" air-fuel mixture that the ECU cannot compensate for quickly enough, leading to stumbling, low RPMs, and stalling.
The Solution: OEM Only
The forum user discovered that their brand-new aftermarket purge valve was internally shorted and stuck open. This is a known issue with the VQ35DE platform: it is highly sensitive to sensor quality.
The Fix: Replace the EVAP Purge Solenoid Valve located near the intake manifold.
Critical Warning: Do not buy the cheapest sensor available. You must use OEM Nissan or Hitachi (the OEM manufacturer) sensors. Aftermarket units often arrive dead or fail within weeks, sending you on a wild goose chase for other problems.
Note: If you are also experiencing random stalling in traffic or timing jumps, check your Camshaft and Crankshaft Position Sensors, as these are also common failure points on high-mileage Z33s.
Recommended Replacement: OEM EVAP Canister Purge Volume Control Solenoid Valve
Frequently Asked Questions
Why does the gas pump keep clicking off when I fill my 350Z?
This is a separate but related issue known as the "shut-off valve" or vent issue. It is usually caused by a clogged charcoal canister or a restrictive vent line. Nissan issued a Technical Service Bulletin (TSB) regarding a shutter valve, but often, clearing the vent lines or replacing the saturated canister solves it.
Can I just delete the EVAP system?
While track cars often delete EVAP to save weight, doing so on a street car will trigger a permanent Check Engine Light and cause you to fail emissions testing. It can also lead to a strong fuel smell in your garage. It is better to fix the valve.
