I drove down to GA last weekend and within 40 miles of my destination I got a SES and the Hoe started to miss. I checked the coolant the next day and was a little low. Expansion tank was full. Over the next 4 days every morning I checked the coolant and it was always low, yet the expansion tank was getting fuller and fuller.

I had my codes pulled at AutoZone and they said I had a code for random misfire all cylinders.

So I threw in a bottle of Sea Foam and replaced the radiator cap and started the drive home. Still having coolant travel into the expansion tank but not pulling back into the radiator and the SES went out for a couple of hours but then came back on. Misfire still happening.

I just had the lower intake gasket replaced 3 weeks ago and replaced the spark plugs and wires at the same time.

 

any suggestions?? It started to smoke again after starting up but clears up 9the smoke) after 5 minutes of driving.

 

Have your cooling system pressure tested.