Weird Starting Issue

I had a weird starting issue last week. With a warm engine (15 miles of driving), I restarted the engine in a grocery parking lot. The engine caught but was shuddering and almost gasping for breath, and all the idiot lights were illuminated; almost sounded like those old prop planes in movies (poh-poh-poh-poh-poh-poh-poh) before they begin to move down the runway, just after the propellers begin to spin. I shut it down and tried again. Same result. I shut it down, waited about half a minute, turned the key and the thing fired up nice and smooth like it always does.

No repeats since it happened. Starting fine every time. Any ideas?

  • List item

#1 Worned spark plugs and cables. (spark plug gab increases with age so the sparks gets weaker)
#2 fuel pump failing or fuel pressure regulator
#3 Mass Air Flow sensor (MAF).
#4 Bad gasoline

I agree it sounds like you had a significant misfire

How many miles on the Jeep?

When was the last time you had an ignition tuneup?

Whichever route you choose to go, I would suggest performing a compression test.

It sort of sounds like the engine was flooded w/too much gasoline. There’s a few possibilities

  • check for diagnostic codes stored and pending, and assess fuel trim numbers.
  • Injectors may be leaking into the intake manifold when the engine is shut off
  • The mechanism which richens the mixture on cold starts is malfunctioning, thinking this was a cold start, when it was really a warm start. Engine coolant temp sensor fault maybe.
  • fuel pressure problem. check the vacuum hose at the fuel pressure regulator, should be no gasoline inside. measure fuel pressure.

There is a Powertrain Control Module software update to address a problem of “Hard to start, long crank time or even a no start” condition, TSB 18-092-16.

The correction is described as “Auto shutdown relay enhancements to improve fuel pump relay initialization at key on”. It seems there may be an intermittent problem with the PCM switching on the fuel pump relay resulting in the lack of fuel problem that you experienced.

PCM software updates are covered by the federal emissions 8 year/80,000 mile warranty.

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I had a similar problem with my last car, a 03 Passat. The same difficulty starting, sounded like it was running on 2 cylinders. Eventually it settled down fine.

This happened about three times over the 10 year life of the car, so I never figured out what the problem was, other than damp conditions.

An earlier car did this only when driving at 70 MPH in rain. Had to pull over and keep it running until something dried out.

Both continued despite replacing plug and HV wires.