99 cadillac runs fine for 30 min then starts running really bad untill it dies and rests for 15-20 min then runs fine for 5 min and does the same thing think its the fuel pump not sure tho

The fuel pressure sounds too low. Is it multi-port injection? Check the fuel pressure against your specs for the car and engine. MPFI systems usually require 40-50 psi.

It can be the issue with weak battery or faulty battery or if battery is ok,then its faulty starter causing the issue.

From start to end troubleshooting these problem i suggest you to click the link below and follow its procedure:-----

What to Do When Car Turns Over But Won't Start?

http://technoanswers.blogspot.com/2012/11/what-to-do-when-car-turns-over-but-wont.html

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Car starting issues?

http://technoanswers.blogspot.in/2012/02/car-starting-issues.html

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Car Starting Problems

http://whoisbyme.blogspot.in/2012/06/car-starting-problems.html

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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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1999 Chrysler Cirrus: 8 IGN Fuel Starter Fuse Blows?

http://whatisbyme.blogspot.in/2012/06/1999-chrysler-cirrus-8-ign-fuel-starter.html

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2001 Toyota Camry: No start After replacing Battery?

http://whatisbyme.blogspot.in/2012/05/2001-toyota-camry-no-start-after.html

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1989 Toyota Pickup Truck: Turns over but not start?

http://whatisbyme.blogspot.in/2012/05/1989-toyota-pickup-truck-turns-over-but.html

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Car dead and will not Start?

http://whatisbyme.blogspot.in/2012/05/car-dead-and-will-not-start.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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2001 Toyota Prius will not start?

http://whatisbyme.blogspot.in/2012/05/2001-toyota-prius-will-not-start.html

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1996 Jeep Grand Cherokee: Engine will not start?

http://repairhelpcenter.blogspot.in/2012/06/1996-jeep-grand-cherokee-engine-will.html

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Mitsubishi will not start

http://www.howtorepairguide.com

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These will help.

Thanks.

check the coolant level. does it over heat. can be a bad coolant temp sensors

My 1986 caddy does the same thing. Did you have any luck fixing yours?
Mike

passably the cover on you motor should stop water from getting in or you got old fuel, or bought bad fuel if possible water in fuel tank buy a bottle of heat this will remove water from fuel tank, replace fuel filter if one or drain moisture trap on engine fuel system.

not sure about your vehicle but it sounds like a coil when they go bad they heat up and open so the engine will get no spark , it's a cheap try.

Sounds like a mass air flow or map sensor fault. Could try running the car with either disconnected, if there is a vast improvement then it is likely to be that part.

a bad crank sensor can cause this. shuts off while going down road, and will start about 10 min, later with no problems runs fine until it quits again. hope this helps,

if car shuts off while driving it could be a bad crank sensor. a bad crank sensor will shut car off while driving, then it will not start for about 10 minutes, when it starts it runs fine until it goofs up again. the popping could be the sensor for it controls timing along with the cam sensor.