P0128 Buick -

Question

2007 buick lacrosse 129,000 or so.-P0128 causes engine lite to come on at times.
It can be on for days and then go out right after starting (before driving) in the am at times.

it will be off for days or so and then back on again.

I thought the light went out when driving after the 3rd
test passed.

When does this test start (at stand still after sitting all night) as that's when it seems goes out ( as a pose to driving and going out)

Coolant level and strength seem ok. Heat is ok. I did notice that
at times the temp. gauge does not reach 11-12 o'clock. It stayed
around 9 for a while.

Would you still think Thermostat? Or could Computer need reset?

Thanks George

Answer 1

More than likely you have a thermostat that is malfunction, when a thermostat  it does it in 2 ways does not open which causes the engine to overheat, or gets stuck open.