1988 v6 4.3 c1500 pickup starts up great. Why does it run like crap until it warms up completely
There is a Idle Air Control Valve that could be all plugged up or bad, you may want to take the throttle body off, pull the IACV out and clean that port along with the throttle body good. Also the Mass Air Flow Sensor should be cleaned also. If the check engine light is on should try and get the code it flashes, there may be a bad O2 sensor also.
One other thing that is the heart of the information going to the computer is the Temperature Sending Unit. It could be bad and you wouldn't even know it.
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