1991cadillac Seville starts rough and dies when its warm

Asked by Apr 17, 2016 at 08:25 PM about the 1991 Cadillac DeVille Sedan FWD

Question type: Maintenance & Repair

I have a 1991 Cadillac DeVille starts great when it's
cold but after I stop and try to start it again it starts
really rough and then it'll die and I have to really put
my foot into it and then the ribs go really high and
then come back down and it does it all the time I've
put in a new fuel pump new fuel filter new EGR
valve new throttle positioning sensor have all my
vacuums checked and it runs great but it doesn't
want to start when it's warm what's my problem

5 Answers

5,875

sound to me like the thermal riser and choke is stuck in the on position~ might be broken...could be jammed shut..but the thermal spring and choke right at the plenum inlet is malfunctioning....sounds like~

5,875

ok... am so old...you've got a thermal sensing goodie on the air intake ...the IAT sensor google this; 1991 Cadillac DeVille Base Sedan intake air temperature sensor --many choices..find one close for quick delivery~

Best Answer Mark helpful

I check my computer I'm not getting any error zero errors it's just when it gets warm it just doesn't want to start it just runs real rough and then dies and then I start it coughs and sputters dies then it starts and runs fine

5,875

well, Kathy the Computer does not know it all...the change in ambient temperature is something the ECU would NOT know...that's why it must measure how cold is it outside...when COLD will enrich the air/fuel mix....in the old days we HAD a heat riser on the exhaust manifold that would push a "butterfly" shut..them days are gone~ all we have are sensors and a computer now~

5,875

Ambient Air Temperature Sensor...have a guy change that for ye~

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