Rep Power: 0

I have a 2005 Honda Civic EX with 105K miles and the car has been experience intermittent misfire (cylinder #2) for the past couple months. When it happens I can feel the car hesitates a little bit at low speed. But the engine really shake when I am trying to accelerate to pass 30mph or going up a hill. I can also hear engine knocking and the engine light will start flashing and then stay on. The problem seems last for a while and go away. The car will then run fine for next 2 to 3 weeks, and the whole cycle starts again. The mechanic replaced all four spark plugs and coil pack, but it doesn't help. Since the problem is kind of come and go, he said it is very difficult to diagnosis. He thinks it could be ECM or knock senor problem. My engine was once overheated several months ago, and the first misfire occurred one week followed it. I don't know if there is any relationship between overheat and misfire. Does anyone ever experienced these kind of problem before? I am not sure what to do next. Do you think dealer will have a better way to diagnosis/fix the problem? Please help..... Thanks.

 
Rep Power: 0

I hate to be the bearer of bad news, but it sounds like you have a blown head gasket. I had the exact symptoms of a slight overheat without any warning and intermittent misfires on cylinder 1 after that. You should have the coolant checked for traces of hydrocarbons. This is any easy test that any shop can perform. You don't want to go too long or else you could risk cracking the head.

 
Rep Power: 812

if youre burning coolant, guaranteed head gasket