No heat from heater, pinging up hills, wants to stall on take off from stop? I changed thermostat last year because heater not giving out heat. It worked. Car has run great. A few weeks ago I noticed it acted like it was going to stall when I stepped on the gas after being stopped at a light.
Then I noticed it started to ping going up hills. Then I noticed the heater quit putting out heat no matter how hot the car is which caused me to notice the temp. Gauge sitting at cold a long time then racing up to half way then back down to 1/4 then up to 3/4 then back down to half. Up and down. I pray it isn't a head gasket as the car isn't worth the repair but all we have.