Hi guys, I have a 2003 Honda Civic Ex, Having problems with it, Multiple engine codes popping up and also it shuts off when i come to a complete stop. it drives fine when i drive at higher speeds but once i start to coke to a stop it will hard idle and sometimes shut off. One time I was stopped and it shut off and turned right back on. I have codes P0341, P0301, P0302, P0303, P0300, P0740, P0420. Also to mention I took the car to the mechanic about a month ago since spark plugs kept going bad, mechanic said he has to change a certain gasket i’m not sure which one, I know It wasn’t the head gasket I had that fixed back in may of this year.

 

If this were me I'd start by clearing the codes, driving around and seeing what comes back. then work from there.

the torque converter code seems to be the outlier. the others may all be related, but the last one is still probably a bad cat. if it's the original it's bad, if it's an aftermarket replacement, at this age it's bad. Probably

has the engine been overheated?
has this mechanic offered to do a leakdown test for you or try out four known good coils?

the gaskets/orings he's talking about are probably from oil getting into the spark plug tubes. not a bad thing to fix, but these are normally a slow enough leak that they aren't fowling the plugs immediately.

A misfire on 3 of your 4 cylinders will definitely make it hard for the engine to idle at a stop without shutting off.

my unqualified guess is ring wear allowing too much oil into the cylinders along with not holding enough compression and causing the misfire as well as the repeat plug fowling. But I don't spend a lot of time on this generation so maybe someone else has a better guess.

 

Yes the Torque converter has been on there forever, but no overheating and I haven’t contacted him, he fixes the gasket back in may and when i took it back when spark plugs kept fowling i thought gasket went bad and asked if he offered a warranty, turns out it was something else and just changed jr without asking me and i don’t want that to happen again. also I did get an aftermarket cat. I still have the oem one but for some reason couldn’t get one of the oxygen sensor off and that’s why i bought the aftermarket one.

 

I've got an '05 that was stalling at the lights. I did a bunch of research thinking it might lead me to a clogged EGR valve. Instead it led me in the direction of a dirty throttle body!
From what I recall, if the dirty throttle body is not allowing the throttle plate to completely close, the IAC cannot take up the difference to increase the idle when, e.g. the AC is on. The result is that the extra load from the AC compressor draws the engine idle down too far for the engine to continue running.
Not sure if that's your issue, but it's worth a shot.

 

If the spark plugs are continuing to go bad, that is your lead. Check to see what kind of damage, oil saturation, coolant, overheat look different.