1994 Mitsubishi Galant starts but shuts off in about 5 seconds

fuel filter might be contaminated by dirt.

Have you changed Fuel pump relay, or plugs/wires?

Its a hot start issue.

Can be related to low fuel pressure or problem with crank sensor.

Also it can be weak battery or starter.

But possibilities are to be inspected to confirm what exactly it is.------

To troubleshoot and confirm the issue,i suggest you refer few solved help links with similar types of problem like yours:------

Click the link below:------

1991 Toyota Trecel: Engine Starts fine but dies when gets Warm?

http://whatisbyme.blogspot.in/2012/05/1991-toyota-trecel-engine-starts-fine.html

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1994 Toyota Pickup: Starts fine but dies in few seconds?

http://howtobyme.blogspot.in/2012/05/1994-toyota-pickup-starts-fine-but-dies.html

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1995 Lexus LS400: Running Hot?

http://whatisbyme.blogspot.in/2012/05/1995-lexus-ls400-running-hot.html

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2002 Toyota Camry: Puff of Blue or White Smoke while Starting?

http://whatisbyme.blogspot.in/2012/05/2002-toyota-camry-puff-of-blue-or-white.html

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Multiple problems on car: Car runs hot, A/C blows hot and car starts surging?

http://schematicsdiagram.blogspot.in/2012/04/multiple-problems-on-car-car-runs-hotac.html

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Delay starting on Toyota Prius?

http://schematicsdiagram.blogspot.in/2012/02/delay-starting-on-toyota-prius.html

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Honda car will not start intermittently?

http://technoanswers.blogspot.in/2012/02/honda-car-will-not-start-intermittently.html

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Vehicle Starts, Runs and Loses Power

http://whoisbyme.blogspot.in/2012/07/vehicle-startsruns-and-loses-power.html

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Intermittent starting issues on Volvo 760?

http://schematicsdiagram.blogspot.in/2012/02/intermittent-starting-issues-on-volvo.html

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Car starts and cuts off immediately?

http://repairhelpcenter.blogspot.com/2012/01/car-starts-and-cuts-off-immediately.html

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Car won't start when cold?

http://schematicsdiagram.blogspot.com/2011/12/car-wont-start-when-cold.html

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These details will help.

Thanks.

You need to check the fuel pressure and to run a fault code test on the electronic engine control system. Also check the cam belt. To run the test go here.

Starts and immediately dies out, sounds like fuel pump. When you turn the key over with out starting it you should be able to hear the pump energize for about 2 seconds.

For 1994 Mitsubishi Galant 2.4L MFI 4cyl the Fuel Filter is located under hood, driver side, upper firewall, mounted in fuel line.

Hope helps.

It is not an O2 sensor. something is shutting down the spark or the fuel, i would exhaust all possibilities with fuel starvation first. have the fuel pressure tested before you go and replace the fuel pump.

this sounds like an electronic problem. the control unit thinks about 50000 cycles in a second. it's bound that there could be a problem. a second hand black box or computer box should fix your propblem. goodluck

could be anything from bad fuel filter to a bad fuel pump to bad plug wires or low fluid levels even dry-rotted vacuum lines ...if the check engine light is on many Auto-zone or Midas stores will diagnose for free.
could be a sensor is bad as well

you need to start with the basics and find if you have fuel, spark. when the no start problem is occuring.