Misfiring Cylinders

[Warbirdone]

I have a 2001 Civic EX with a 1.7L engine. I have been having a random intermittent misfire on cylinder 1 for the last few months. I changed the spark plugs, tried a few injector cleaners, and the engine light would sometimes turn itself off for days at a time before coming back on. Then suddenly it started having random misfires on all 4 cylinders and I got 2 cat converter codes. The engine has only stalled once, normally it doesn't even come close. But it definitely changes it's mind on idle speeds a lot. Starting up is usually around 1200 and it'll adjust between that and 700 or occasionally lower. I also seem to have a loss in horsepower at low gears and low rpms, it'll hesitate when accelerating. The engine also overheats after driving for awhile coming to a stop for an extended time, and I'll find the reservoir full or even overflowing, and the radiator empty. I thought maybe the cat might be causing the misfires with backpressure, and the overheating with nowhere for the exhaust to go. So I completely took off the exhaust pipe from the headers back just to test it. There seems to be no more hesitation, but I now can still hear the occasional pop of the misfires at low speeds. Any suggestions as to what else may be causing the misfires?

 

[RonJ]

Do cylinder compression and leak down tests. The head gasket may be blown.

The likely events that brought you to this point are a blown head gasket caused misfiring which in turn destroyed the catalytic converter.

 

[FreeOfThoughts]

def sounds like head gasket if your coolant is bubbling and overflowing, that happened to my dads acura last year, started overheating, coolant bubbling over in the reservoir, it was a head gasket.

 

[westendhooligan]

yeah sounds like a blown head gasket! that or your valve clearance are jacked up!

 

[gudoffer]

had the same problem...blew my gasket... tried to change the radiator, thermostat nothing worked...

i got the head gasket changed along with timing and water pump...so it was kinda costly from honda but with 20 000 km warranty, it is worth it...

ull need to do a engine leak down test...my cylinder 3 was leaking.

but engine leak down test will tell u...

if u end up doing an head gasket repair...i would say get a whole head gasket kit (comes oem from honda for $280) , it has all the gaskets seals and bla bla...

plus in addition, i added more money and got my cam and crank seals changed....just for my own benefit while he was there...