Q: My car stalls arbitrarily and with no warning and is getting progressively harder to start.

asked by on

I bought a used 99 Dodge Intrepid a couple months ago. Soon after, it stalled in the hwy at 65 mph with no warning. The tach simply dropped to zero. Other than the cruise control light coming on, nothing was different. I pulled off with my flashers and it started right back up. The next night, it happened again- took a few minutes to start back up. It has since progressively become harder and harder to start. The other night, it wouldn't start for a few hours. So, the online "research" I've done overwhelmingly points to the camshaft and/or crankshaft position sensors as well as a possible cat converter problem. I got 3 trouble codes from the odometer 1. P1684: battery disconnected within the last 50 starts (which I had definitely not done) 2. P0420- Catalyst system efficiency below threshold (bank1) 3. P0432--Main catalyst system efficiency below threshold (bank2). I keep hearing that I should start with the Camshaft position sensor, as its the easier one to fix

My car has 217000 miles.
My car has an automatic transmission.

Hello and thank you for contacting YourMechanic. The code P1684 means that there was a battery disconnect from a sensor to the computer, or in other words, a sensor has lost communication with the computer. The code P0420 usually means that the catalyst converter is not functioning correctly. The code P0432 means that the catalyst converter could not functioning or there could be a problem with the fuel to air mixture.

Most of the time when these codes are present, there is a problem with the fuel mixture and causing the catalyst converter to work harder. The camshaft sensor will cause an engine to have a no start situation along with an incorrect fuel ratio. I recommend replacing the crankshaft sensor, replacing the camshaft sensor, and cleaning the MAF (Mass Air Flow) sensor. This should keep your vehicle in top shape and no issues. If the problem continues, have a professional mechanic, like one from YourMechanic diagnose the stalling issue and proceed with repairs.

Was this answer helpful?

Need advice from certified mechanic? Get help now!

Over 1,000 mechanics are ready to answer your question.
The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details

Ask a Mechanic
(100% Free)

Have a car question? Get free advice from our top-rated mechanics.

Ask A Mechanic
Over 10,000 questions answered!
  1. Home
  2. Questions
  3. My car stalls arbitrarily and with no warning and is getting progressively harder to start.

Get an instant quote for your car

Our certified mechanics come to you ・Backed by 12-month, 12,000-mile guarantee・Fair and transparent pricing

Get a quote

What others are asking

Q: Brake rotor diameter

According to the parts listings, the front rotors are the same size across the line. The choices are when it comes to rear brake rotors. The 10.31 inch rotors are for the 2 wheel drive models and the 11.89 inch...

Q: Q: My car won't shift gears

Hi there. When this transmission starts sticking in gear like this it is typically the first sign of an internal transmission failure. The solenoid pack should not have to be installed prior to checking the transmission pressures to see if...

Q: Loss of power, weird sounds from the engine and hissing sound from throttle body, and a code P1346 1999 Lexus IS200

Hello - the P1346 problem code you have indicates a camshaft timing problem (variable valve timing to be specific), and is at least part of the cause of low power. The cams are out of time, relative to the crankshaft....

Related articles

How Long Does a Heater Control Valve Last?
Keeping the right amount of coolant in a car is essential in keeping the engine at the right temperature. Failing to have the right amount of coolant or even bad elements...
P0240 OBD-II Trouble Code: Turbocharger Boost Sensor B Circuit Range/Performance
P0240 code definition Turbocharger Boost Sensor B Circuit Range/Performance What the P0240 code means P0240 is an OBD-II generic code triggered when the Engine Control Module (ECM) detects the intake boost...
Rules of the Road For Iowa Drivers
Driving on the roads requires knowledge of the rules, many of which are based on common sense and courtesy. However, even though you know the rules in...