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The catalytic converter needs to warm up to a running temperature and various operation in the engine devote energy or fuel to this process. Once the catalytic converter has reached this "running temperature" it can easily maintain this temperature with the heated exhaust from the engine. One of the "warming up" components is malfunctioning, most likely the pre- or post injection of the fuel into the engine which is one of several methods of "warming up" your catalytic converter.
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Why would a 96 gmc sierra stall and run rough until the engine is warm?
It stalls even when warm
Why does your engine run rough when hot but not when cold?
becuase the bolts and everything really loosens up
Why does 1998 dodge 1500 ram run ok when cold but runs rough and stalls when warm?
temp senser or spark coil
Why would an engine run cold temp gauge says cold and the heater blows slightly warm air?
change t.stat
Will a high performance engine run better in cold or warm weather?
A high performance engine will run better in the cold the vehicle is at full operating temperature. Cold air is more dense so basically its like your packing in more air into the cylinder.
Why does my 91 Dodge shadow runs smooth when it is cold when it gets warm it starts to run rough and not smooth?
Maybe a faulty coolant temperature sensor. The air-fuel mixture is rich when cold, which is OK, but as the engine warms up, your mixture is too rich. Is your fuel economy suffering, too?
What would cause 99 express to not start when hot but run fine when cold?
the temp sensor that reads low will cause the engine to run very rich which is fine when it's cold, but will flood it when warm.
Run good when cold warm up run ruff?
This could be due to several factors such as faulty sensors, clogged fuel injectors, vacuum leaks, or worn spark plugs. I recommend having a mechanic run a diagnostic to pinpoint the exact cause of the rough running when warm.
Why does your 1992 Saturn sl1start to run rough and backfire after engine is warm?
check your coolant temp sensor also is the ses light on,posible egr fault
1992 Corvette w 5.7 LT1 engine Cold startup want to die until you keep foot on it till its warm Also idles rough but open road runs great.can someone help?
check coolant temp sensor, the computer is still running on open loop, doesnt know engine is cold, unplug sensor, it should run the same, do you have check engine light on ??
Should the engine be warm or cold when you check the oil level in an automotive engine?
Makes no difference if the engine is warm or cold. Just make sure the engine has not been run for at least 30 minutes before checking the oil level. This way you will get a very accurate reading. I normally check my oil level after the car has sat overnight.
WHY DO OLD CARS RUN ROUGH WHEN COLD?
They had carburetors back in the days of old (pre-1980's). If they weren't adjusted just right or operating properly they ran rough until the engine warmed up.
