Jeep Stalling While Driving

Question:
1992 jeep wrangler 4.0 automatic dies while driving and noticed that fuel gauge goes to full every time and will come back down after a few minutes and jeep will start right up and run normal until fuel gauge goes back up.

Answer;
There are several reasons that could be the cause of your jeep stalling while driving and the most common one is vapor lock. This can happen when you engine becomes abnormally hot.

So the first question you need to answer is does the stalling only happen when your jeep engine is abnormally hot?

Yes the stalling does happen when my jeeps engine is abnormally hot.

No the stalling doesn’t happen when my jeeps engine is abnormally hot.

If your jeep is stalling when your jeeps engine is abnormally hot then the cause is more than likely vapor lock.

Vapor lock is caused when your gas boils before it reaches the engine. When you engine becomes abnormally hot your gas will start to boil causing air bubbles to form in the gas. This will cause your air/fuel mixture to become too lean. (too much air and not enough gas)

The cause of this is more than likely a problem within your jeeps cooling system. The two things to look at here are a bad thermostat, or the cooling system being clogged up.

Replacing your thermostat and flushing out your cooling system should resolve the problem of jeep stalling while driving.

If your jeep isn’t stalling when your jeeps engine is abnormally hot then the likely cause is a lack of fuel getting to the engine.

The 1992 jeep wrangler with the 4.0 L engine has fuel injection and the fuel is regulated by a fuel pressure regulator. A bad fuel pressure regulator will result in not enough fuel getting to the engine and your jeep will stall while driving.

You would need to take you jeep into a mechanic to verify that your fuel pressure regulator is faulty. If it is faulty you can have the mechanic replace it, or replace it yourself.

If you have the mechanic replace the fuel pressure regulator, don’t let them talk you into replacing any other parts at this time. You can always come back later and have other parts replaced if needed.

If you replace the regulator yourself, I’ve provided a photo of what they look like below. The photo is not of great quality, but it should help if you decide to do the work on your own.

NOTE: Either of these could possibly be the cause of your fuel gauge going to full.