Why does my Chrysler 300M lose power, die or not start?

Short answer: If a 300M cuts out at highway speed and then dies with code P0340, the camshaft position sensor or its wiring is the prime suspect. Without that signal the computer may shut down fuel and spark. If it's instead hard to start after it's already been run once that day, try a flood-clearing start; if that works, a leaky fuel pressure regulator or injector may be flooding it.

Symptom: Power drops out for a moment on the highway, then one day it dies and won't restart. Or it starts fine the first time but sometimes won't start later in the day.

What to check first

1. Read the codes. P0340 points to the camshaft position sensor circuit.
2. Inspect the cam sensor wiring and connector.
3. For hard starts, try a flood-clearing start: gas pedal to the floor while cranking. If it starts that way, it's likely flooding.
4. Check fuel pressure hold for a leaky regulator or injectors.
5. Check for spark at the coil-on-plug ignition when it won't start.

Likely causes

1. Camshaft position sensor or wiring. Code P0340; can cut power and stop the engine.
2. Leaking fuel pressure regulator or injectors. Can flood the engine after it's been shut off.
3. Ignition coil. Each plug has its own coil; test for spark.

What it usually costs

No owner in these threads posted a repair bill. Members said the cam sensor on the 3.5L is easy to change, usually held by one bolt.

Is it safe to keep driving?

No. Losing power at highway speed is dangerous. Get a P0340 fixed before driving far. Verify with a mechanic.

DIY or shop?

DIY for reading codes and replacing the cam sensor. Fuel pressure and injector testing usually needs a gauge or a shop.

Recalls, bulletins and complaints in plain words

• Recalls: NHTSA lists no recall for stalling or no-start on the Chrysler 300M for these model years (checked 2026-10-24). Other recalls may exist for your car, so check your VIN at nhtsa.gov/recalls. If your car is part of a recall, the dealer fixes it for free.
• NHTSA complaints: 91 keyword-matched complaints for Chrysler 300M 1999–2004 (of 898 unique complaints queried, NHTSA complaints API by model year, queried 2026-10-24; keywords: stall, dies, shut off, won't start, no start, cuts out, idle, sensor, power). This counts complaints that mention these words. It is not a defect finding.

What owners report

• In 1999 Chrysler 300M Power cut-out , Engine died, won't start on Car Talk, a 1999 300M had occasional power loss on the highway, then died and wouldn't start, with code P0340. Members said the camshaft position sensor or its wiring was the likely problem, that without it the computer doesn't know where the engine is in its cycle and may shut down, and that these sensors are easy to change.
• In "03 Chrysler 300M Special -- Occasional Hard Start Issue on Car Talk, a 2003 300M with 96,000 miles and a recent tune-up, timing belt and cam sensor was sometimes hard to start after the first start of the day. Members suggested trying a flood-clearing start; if that works, suspect a bad fuel pressure regulator or leaky injectors. Another said to test spark, fuel and air at the moment it won't start.

Quick tip

P0340 on a 300M is usually a cheap fix. Do it before it leaves you on the shoulder.

Vehicle focus: 1999–2004 Chrysler 300M with the 3.5L V6. The Concorde, Intrepid and LHS of those years share similar parts.

Safety / mechanic note

Losing power at highway speed is dangerous. Verify with a mechanic.