1990 Cadillac Deville Missing

Tiny
DUSTYLIST
  • MEMBER
  • 1990 CADILLAC DEVILLE
  • V8
  • FWD
  • AUTOMATIC
  • 127,000 MILES
My deville has just started running very rough and missing under acceleration, I have tried injector additive but it still stumbles and kinda has a very funny sound like a clyinder is not firing, I notice a slight coolant smell when I turn it off and no noticable smoke out the exhaust could it be a head gasket blown between the cylinders or does it just need plugs and a tune up, cap and wires? I have been running regular gas and add a can of lucas injector cleaner every once and a while, thanks for the help
Thursday, June 11th, 2009 AT 1:54 PM

1 Reply

Tiny
RASMATAZ
  • MECHANIC
  • 75,992 POSTS
1990 Cadillac Deville Missing

Dirty fuel injectors (cleaning the injectors often fixes this).
Bad MAP (manifold absolute pressure) sensor
Bad TPS (throttle position) sensor
Bad or dirty MAF (mass airflow) sensor
Low fuel pressure (leaky fuel pressure regulator or weak fuel pump)
Vacuum leaks (intake manifold, vacuum hoses, throttle body, EGR valve)
Bad gasoline (fuel contaminated with water or too much alcohol)

Sometimes, what feels like a hesitation is actually ignition misfire rather than lean misfire. The causes of ignition misfire may include:

Dirty or worn spark plugs
Bad plug wires
Weak ignition coil
Wet plug wires
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Thursday, June 11th, 2009 AT 4:43 PM

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