Why does my Chrysler Fifth Avenue idle rough and stall, or not restart when warm?

Short answer: If your Fifth Avenue idles rough, shudders and stalls even after a carburetor cleaning, check the EGR valve and the AAP diaphragm, set the timing and idle mixture, and consider a carburetor rebuild with ethanol-resistant parts. If it starts cold but won't restart warm until it cools for hours, members pointed to the engine temperature sensor.

Symptom: The engine shakes at idle and may stall at a stop. Or it starts fine cold but just cranks after it's warm, until it sits for a couple of hours.

What to check first

1. Check the EGR valve for sticking open.
2. Check the AAP diaphragm for leaks.
3. Replace the cap, rotor and wires if they're old.
4. Set base timing and idle mixture to the underhood label.
5. Test the engine temperature sensor for a warm no-start.

Likely causes

1. Carburetor needs a rebuild. The electronic feedback carburetor mixes fuel and air. Members suggested rebuilding it with ethanol-resistant parts.
2. Leaking auxiliary accelerator pump (AAP) diaphragm. A leaking AAP diaphragm can make the engine run rich (too much fuel).
3. EGR valve stuck open. The EGR valve sends some exhaust back into the engine. If it sticks open at idle, the engine stumbles and stalls.
4. Ignition parts, idle mixture or base timing. Cap, rotor and wires, plus idle mixture and base timing, were on the members' checklist.
5. Engine temperature sensor (warm restart). For a car that won't restart warm, members pointed to the engine temperature sensor.

What it usually costs

No owner posted prices in these threads.

Is it safe to keep driving?

Stalling at stops or in traffic is a crash risk, and you lose power steering and power brake assist when it stalls. Get it fixed before relying on it. Verify with a mechanic.

DIY or shop?

Mixed. EGR, ignition parts and sensors are DIY. Carburetor rebuilds go best with a carburetor specialist.

Recalls, bulletins and complaints in plain words

• Related recalls: NHTSA lists this recall touching this area of the Chrysler Fifth Avenue: 87V164000 (1988 model year, fusible link wires in the engine compartment harness may be trapped under the speed control servo bracket). Check your VIN at nhtsa.gov/recalls. If your car is part of this recall, the dealer fixes it for free.
• Plain words: Recall 87V164000 covered fusible link wires that could get pinched under a bracket, which can cause a short. It doesn't cover rough idle, but check your VIN. Verify with a mechanic.
• NHTSA complaints: 5 keyword-matched complaints for Chrysler Fifth Avenue 1982–1989 (of 28 unique complaints queried, NHTSA complaints API by model year, queried 2026-10-28; keywords: stall, idle, rough, start, carburetor, hot) (NHTSA returned no data for 8 model-year queries). This counts complaints that mention these words. It is not a defect finding.

What owners report

• In 1989 Chrysler Fifth Avenue still idling rough/stalling after carburetor work? on Car Talk, a 1989 Fifth Avenue idled rough, shuddered and stalled. The owner had cleaned the electronic feedback two-barrel carburetor with a new gasket and replaced a resistor and the preheater hose, but it still did it. Members suggested a carburetor rebuild with ethanol-resistant parts; new cap, rotor and wires; checking idle mixture and base timing; an EGR valve stuck open; and a leaking auxiliary accelerator pump (AAP) diaphragm, which makes it run rich. They noted Lean Burn is Chrysler's ignition computer, not the fuel system.
• In 1987 chrysler fifth Avenue issues on Car Talk, a 1987 Fifth Avenue started fine cold but wouldn't restart warm until it had cooled for about two hours. It was also overheating after about 11 miles, and a new starter and hoses hadn't fixed it. The owner suspected the thermostat or coolant temperature sensor, and members pointed to the engine temperature sensor and the cooling problem.

Quick tip

On these carbureted Chryslers, check the cheap stuff (EGR, timing, cap and rotor) before paying for a carburetor rebuild.

Vehicle focus: 1982–1989 Chrysler Fifth Avenue (US).

Safety / mechanic note

Let the engine cool before working near the exhaust or the carburetor. Verify with a mechanic.