I own a prelude with a h23a. I've been running with a messed up ignition coil for i don't know how long, and code 12 pops up whenever I drive on the freeway.

One thing is that it comes on sooner or later depending on what city I get gas at. I have tried cleaning the carbon out of the passage, and it helped, but then it got worse again. I think maybe cuz of the coil, it is putting alot of unburned mixture in there causing it to clog. Any input would be great.

 

What is code 12 and is your car misfiring? If your not misfiring then move on. Well that could affect the EGR and cruise because that when the EGR open and closes. So you should check the EGR valve location on the driver side fenderwell. There's a filter in there so it could be clog and you should blow out the valve with compress air

 

code 12 is egr malfunction, and yes it does misfire sometimes, also there is no filter in the egr man, I took one apart before.