Question about 1991 Cadillac DeVille
Starts and runs fine as long as you don't stop. Once you stop and let idle for a couple of minutes the engine light comes on and the engine begins to run very rough. Will run great with lots of power as long as you are driving. Can restart and drive and it starts the same cylcle again.
True of many cars. Happened to me too many times, fourin
Posted on Dec 25, 2012
The idle may be to low or the motor is just old and a new set of rod bearings is need with an oilpump to bring the pressure back up.
Posted on Jul 14, 2009
SOURCE: rough idle after warm up
I'd take a look at the temp sender...the engines computer may be
"thinking" the engine is still cold when it's not. That would cause it
run rich (and rough) after it's warmed up. Generally the sender can be
tested with an ordinary volt/ohmeter but you will need the
specifications available in most inexpensive manuals. As with any
complicated electronics system, I can only give you my best guess,
without the luxury of doing any hands-on testing myself.
Posted on May 28, 2009
I have a 95 eldorado that is starting hard and idling rough. Also noticed gas pedal fluctuating. I have been told it is the Fuel Pressure Regulator. Does that sound reasonable?
Posted on Jul 09, 2010
E13: right bank O2 sensor, no data
F48: low refrigerant level in A/C system
Neither of these is likely to cause rough idle, but I would change the sensor.
If that cure it, great.
If not, make sure the vacuum hose on the fuel pressure regulator (at end of fuel rail) is tight at both ends and not cracked or leaking. Then pull the vacuum hose off the regulator and see if there is any fuel in the vacuum hose. If yes, replace regulator.
I also recommend cleaning up the intake side of engine with carb cleaner or equivalent: throttle body, Mass airflow sensor, EGR system, and PCV valve. Make sure EGR valve is operating.
If you have questions, please let me know.
fuel press reg:
Posted on Oct 24, 2010
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