Surge and sputter at cold start

[scw7080]

Hi,
I own a 1987 Grand National and when I start it cold it idles decent for the first 20-30 seconds. Then the engine surges, sputters, and continues to do this 4 or 5 times. Sometimes the engine even stalls. In fact, if you start it cold and immediately take off driving the engine will stall. This is not a problem when the engine is warm. Also when you step on the accelerator there feels to be a split second lag. The spark plugs, spark plug wires, and throttle position sensor are all new and properly installed and there is nothing wrong with the head gasket. Any ideas? Thank you.

 

[750H.P.V6]

If the car is all stock with a stock chip it's not that uncommon. The cold start table is calibrated pretty lean from the factory. Most aftermarket chips have some more fuel added to help the problem. The problem can be compounded by a MAF sensor that reads low. If the MAF has been replaced with anything other than a OEM MAF its likely a contributing factor.

Neal

 

[mearly65]

^x2. I had the same problem. Put in a Turbo Tweak chip and it never happened again

 

[TurboBuRick]

ECM data might shed some light.

 

[GNONYX]

I do agree with others of replacing the ECM Chip with Full Throttle or Turbo Tweak chip, but have you also remove and clean the IAC and the throttle body? You might have carbon buildup after many mileage years.
Read this site: http://www.vortexbuicks-etc.com/basics.htm#IAC (Idle Air Control) Adjustment