Maybe too cool?

[jackmalone2001]

Hello to all!

Referencing a previous post of mine, where I had said my 1999 Le Sabre temp was too cool (110f-120f), it was recommended to change the thermostat. I am noticing a "stuttering" on the highway, when I am accelerating at highway speeds (to pass another car). Could the two issues be connected in some way?

Autozone says there are no codes and I replaced the spark plugs. Wires look brand new. Fuel filter will be replaced this weekend. I may change the thermostat.

What do you think? Can a car running too cool effect performance and cause a stuttering at speed? Please give me your thought!

Thanks! Jack

[BNaylor]

It could. That temperature is too low and the PCM module may not be switching from open loop mode to closed loop mode as a result or when it should. Also, it may cause a rich trim situation to the fuel injection system because the PCM module thinks engine has not reached proper operating temperature. But interesting to see you are not getting a P0128 DTC. Sounds like your thermostat is stuck open which you will see if you remove and inspect it. Also, you could check the calibration (resistance) of the engine coolant temperature sensor (ECT) to see if is giving the proper output based on actual engine temperature.

But try the thermostat first. Be sure to use a good quality one like the AC Delco Premium Series or the Stant Superstat rated at the OEM 195 degrees.