Mechanics

WHY DOES THE ENGINE MISS ON COLD STARTUP,AND NOT WHEN AT OPERATING TEMPERATURE?

2000 Chevrolet Blazer • 190,000 miles

2000 blazer 4x4 has new tuneup, new TPS, new IAC, new MAP sensor, checked EGR valve for carbon buildup, very little and function. Did not check for electrical, though. It was in closed position and seated when I pulled it. On cold startup in morning, starts fine, idles fine, idles down fine, when I start driving it, it has a severe miss until it reachs operating temperature. It runs fine after reaching peak operating temperature. It is now 78degrees in morning and 100degrees in the afternoon. Hope you can make some sense of this, and give me some solutions. Thanks, Robert
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Robertd55
September 5, 2012.



Could be injectors needing service. Could be carbon on the intake valves.

Did you replace the wires and cap and rotor?

Roy

Yes and this missing did not start till 3000m later.

Tiny
Robertd55
Sep 6, 2012.
Have the injectors professionally cleaned. Gas tank additives have little or no effect.

Roy

Since Ive had the vehicle Ive always added Lucas or something similar to tank. Thanks, Robert

Tiny
Robertd55
Sep 6, 2012.
Not good enough. Theyy need to be direct injection cleaned.

Roy

Then, why would it not miss all the time, after it warms up also?

Tiny
Robertd55
Sep 6, 2012.
If it had a dirty injecter would it not miss all the time?

Tiny
Robertd55
Sep 6, 2012.