Proper course of action when car engine suddenly dies occasionally when car is stopped

Question

When I was driving home from work today I stopped at a traffic light. The car was stopped and in drive, and my foot was on the brake. I was on relatively level ground, and the ground was relatively smooth (no debris). The engine was not hot, and it was during a cool night.

I noticed that the engine turned quicker than usual a couple of times: the RPM meter showed that the engine was turning slightly over 1000 RPM (even though the car was stationary and my foot was on the brakes) for a couple of times, then the engine suddenly turned off (the display was lit, but the car would not accelerate if I lifted my foot off of the pedal while in drive). I was able to move the gear-shift to park, turn off the battery and ignition, then turn the ignition, battery, and engine on successfully. I didn't encounter any more issues on the way home.

This is the second time I experienced this issue. The first time was last week, and the conditions were the same.

I drive a 2003 Lexus RX300. The engine was last replaced in November (a little over 3 months ago).

Is this sufficient evidence to warrant seeking auto-repair? If so, what should I reasonably expect?

I can provide more information on request. Thank you :)

EDIT: Title change.

Answer 1

If you have a car that is stalling the problem is unlikely to go away, in fact it is likely to get worse. It could be a problem that is cheaper to fix now than later. Also, an engine stall could put you in a very inconvenient or even dangerous situation (it's happened to me), so you have every reason to get it fixed, and no reason to wait.

As for what could be happening, there are many possibilities:

• Fuel filter
• Fuel pump
• Bad fuel
• Airflow sensor
• Air temperature sensor
• Engine temperature sensor
• Oxygen sensor(s)
• Engine Computer failure
• Fuel injector
• Spark plug
• Spark plug cable
• Ignition coil
• Airflow restriction
• Vacuum leak
• Loose manifolds/leaking manifold seals
• Gremlins (not really but sometimes I almost believe in them)

That's all that immediately comes to mind, but there's more that could be wrong. Some of the above are more likely than others from your description. It sounds like a hugely daunting thing, but fortunately your car has on-board diagnostics called OBD2 which can be read using a reader, and often the codes will point to the problem. You can get these codes read at most auto parts stores or you could buy a reader and do it yourself, bluetooth ones are very inexpensive these days.

If there is a code or codes you fix the problem shown by the codes unless the codes don't make sense. If there are no codes it gets more complicated, you have to look at what the car can't detect in which case my money would be on a vacuum leak.

If you want to have a look into this yourself then I would suggest reading your codes, also looking under the hood for anything obvious like frayed/oil soaked ignition cables, signs of leaks, loose hoses, etc. If you get codes use the search function on this site to look for your codes and see what previous questions and answers are there to solve your problem - there are many questions and answers out there about codes. If there aren't any previous questions with your codes then by all means ask a new question about them, it's why we're here.

Answer 2

The engine replacement may have come with a warranty. You can take it back to them and see if they can diagnose and repair under warranty before you make any repairs that might void the warranty.