Runs rough and misses badly when cold. once warm it runs fine.

Clean the Throttle Body and Mass Air Flow Sensor. Also check for DTCs (diagnostic trouble codes).

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Diagnose Engine Misfire - Auto Diagnosis Repair Help

www.aa1car.com/library/misfire.htm

The engine may shake so badly at idle that it causes vibrations that can be felt in ...The engine may only misfire and run rough when cold but then smooth out as ...

What is causing an intermittent misfire only when engine is ...

community.cartalk.com/.../what-is-causing-an-intermittent-misfire-only-...

Jun 27, 2013 - NOTE: You MUST restart the engine for the misfire to go away. ... in an expert to do that test, but it might be worth it to prove/disprove the injectors being thecause. 0 ... The first is that the car should run fine even on cold starts.

Engine misfires when cold but runs fine after warming up few ...

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Mar 24, 2009 - They also gave it to me because of this misfire problem it has. ...Engine misfires when cold but runs fine after warming up few minutes later? ... and you start next morning will also cause a misfire until it burns off the coolant.

"Miss/splutter" with cold engine, but fine when warm? M103 / also ...

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Jul 13, 2011 - My moms old 300SEL (with the M103) that was once my car is now my "work car" again as she is getting a brand new SUV very soon.

Cold start misfire solved (finally!) - Bimmerforums

If you have a carb its chock .If injection its fuel related filters regulator restrictions if fuel flow ect.

02 sensore after the cat

The code is for a miss-fire on cylinder two, it could be from a faulty spark plug or injector among other things.
Once you get above 2000 rpm the other 3 cylinders can cover the loss of power.

Buick 97 lesabre, runs rough when warm

Sounds like possibly more than on problem, crankshaft position sensor, or ignition module likely on starting prob which maybe affecting shifting due to hard code in ecm, or shift prob could be shift solenoid in valve body of transmission. Both parts readily available from local parts store

EGR valve or system is bad. that is Exhaust Gas Recycling valve. It's a pollution device that recycles exhaust gas back through the engine once it warms up. It's not suppose to work while engine is cold so there is a thermostat system for it that closes off the EGR valve while engine is cool. Once it warms up then it opens the valve. If you're recycling exhaust gas while engine is cool it will run rough. This can be hard for the average guy to troubleshoot as you need check the vacumn switches and thermostat valve.

Check to see if your spark plug wires are not cracked or worn. They would make the engine run rough when cold or damp more often then when the engine drys up when warmed up- just an easy thing to check...