First, thanks for reading and I appreciate any advice that anyone has. I'll try to keep this short (but I will fail), but I'm going to lay out exactly what has happened and what I've done.

I've got a 2001 Civic EX coupe. It's got about 187k on it. I bought it in 2005 and have maintained it very well. Except for a badly chipped up hood, it looks brand new inside and out. I've done most of the repairs and fun stuff to it myself when possible. I am no mechanic, but I learn something new every time I have a problem, I enjoy fixing it myself and saving money. I love the car and also can't afford car payments, so I've got to keep it as long as I can. I'm committed, though I'd love a new SI.


Here's what happened:

Starting sometime around Oct 2012 I noticed out of the corner of my eye, my CEL came on for like half a sec. I thought I was seeing reflections off the panel or I was going crazy. It goes off so fast you aren't sure you saw anything. Finally happened once when I was looking at the speedometer so I knew it was really coming on. It happened like maybe a few times a week. So 3-5 times for a split second during about 10-15 hours of driving. i tried pulling the code, but I guess it never stayed on long enough and nothing registered.

Around this same time, the car started driving bad. Not horrible, but when maintaining speed, say like 4th gear at about 40mph it was most noticeable, it felt like a pulsating or kind of mild shuddering. Could feel it in the steering wheel and the gas pedal. I ruled out tire balancing and alignment as I have had consistent issues with both of those and I know how they feel, which is different.

Around the same time, my alternator died and then my starter. I replaced them. Obviously had nothing to do with the problem, I knew that. But CEL still coming off and on. a few months go by. I felt like the problem had to be something motor related, like cylinders or maybe fuel injectors. Just felt like it was running off balance. A few car guys like my father in law didn't agree, and in the end my intuition was right. But I went through the motions. I used heavy duty injector cleaner, did nothing. I had never changed the spark plugs before, so I figured maybe that's it since they're probably 12 years old at this point. Did that. no change. Also bought new coil packs. No change.

Finally around May 2013 my CEL came on and stayed on. I was never so happy to see that light on. Ran the code, P0300, 302, 303 etc, cylinder misfires. There was also a code for the evap system (P1457).

Now I was thinking maybe it was the purge valve not opening so maybe fuel vapor was building up and causing the misfires (maybe that's stupid, but as I said, not a mechanic). I replaced the purge valve. CEL went off. I thought it was all fixed. Nope, still driving bad. a week later, CEL coming on briefly again.

Finally decided I'm out of my league and brought it to a shop owned by a family friend. He couldn't figure it out. Ended up bringing to dealership next. They said my fuel trim level was at 1.15 so injectors were staying open too long and did a valve adjustment. Car drove better than it ever had as long as I owned it. It was so smooth. That lasted a month.

August 2013, CEL flashing off and on briefly again. Driving just as bad as it was before, though my fuel mileage which improved after the adjustment they did, stayed good. Brought it back to Honda. They couldn't find anything wrong, despite it doing the exact same thing. It was more like they didn't want to check anything without the code. It was also a different mechanic than the one that worked on it last time. So this guy didn't think the car drove bad. So no code, no service. They told me to come back when CEL stayed on.

So it took about 3 months for the CEL to once again stay on. Two weeks ago, ran the code, P0300, 302, etc. Same thing. Brought it back to Honda again. This time they said that the fix they did last time was still good, but this time it's the EGR valve and bad carbon build up in the ports. I debated doing this myself, but I hurt my back recently and have a lot of other things going on, so I didn't have the time. I had them do it despite the cost.

I got the car back last week. Driving beautifully again.

Today, I noticed the CEL came on briefly again a few times on the way home from work. Car is still running good, but I'm worried in a few weeks it will be driving bad again.
So what I'm wondering is, after everything I've done up to this point, if it starts driving poorly again and if the code comes back as cylinder misfires again, what would you check next?

I would just like to approach Honda as informed as possible. I do sort of trust this dealership, and they also know that I know my car inside and out, but still. Also maybe I'm jumping the gun, maybe there's something else going on. But, it could also be weeks or months before I can check the code again, which is really frustrating. It sucks driving it when the cylinders are misfiring, and I feel like it can't be good for the car, and as I said, I need to keep this car for a looong time.

Sorry for the novel, and I appreciate anyone who takes the time to read it and give me advice.

 

Check fuel pressure. The pump and filter are supposed to last the life of the car but, "life of the car" is totally different for Honda than it is for us.

Also, pull the EGR valve and check to see if they really did change the valve and clean the ports.

 

Sorry not really able to help you, do purchase a low dollar code reader with the ability to record fault codes, and keep it plugged in.,

 

I use this one: http://www.mactools.com/product/tabi...9341-ET97.aspx If you look you can find them for about $80.

 

I would guess that they did at least clean the port since the car is running better, but Yeah I agree with you on checking. Afterall, I had this place do my timing belt in 2011 and they gave me my car back with no oil in it.

Cool, I'll check the fuel pump and filter. At this point that's probably the only stuff on the car that's never been replaced.


So this code reader you guys are talking about, you think it will catch the code even if the CEL doesn't stay on if I leave it plugged in?

 

In a word- yes.

Note: Don't start the car with it plugged in.

 

Ok cool, thanks

 

I've had a few cars with issues like this come in sometimes these motors have jumped timing due to lack of maintenance believe it or not. Had a Pilot come in not to long ago with misfires on cylinders 1,2,3 and when I checked the timing, I found the cams were off 2 teeth from TDC. So that's one thing you could check.

Also, when you replaced the alternator did you replace it with a factory unit? Sounds weird but had one of these cars come in with an aftermarket alternator on it with a misfire and the alternator was actually the culprit. These cars are very sensitive to noise which will make the car do some funky thing. Sit in the car in 'P' and rev the motor to see if you can get it to mis. If it doesn't, it's more than likely not your problem.

I would check for vacuum leaks as well. Easiest way would be to get a can of carburetor cleaner and spray around anything that leads to the intake manifold. If you hear the engine idle raise while spraying a particular area, a leak is present there. BE CAREFUL if you use this method as carburetor cleaner is volatile and can catch fire if sprayed near hot engine parts. Also the easiest way to check for leaks in vacuum line would be to just remove them off of the intake manifold and cap the port off with your finger and check your scan tool. If you remove a line and cap off the port and the fuel trim on your scan tool starts to go down, there is a leak in this line or component this line is feeding.

I wouldn't put too much effort into the fuel pump. I mean if you have access to a fuel pressure gauge it won't hurt but from my experience, I have yet too see a Honda pump fail but hey, anything can happen.

Let us know what you come up with and we can tell you where to go from there.

 

I got an alternator from Autozone. I'm trying to think if the misfire problem was happening before or after that. A bunch of things all went wrong right at that same time so I can't remember. But I will check that.

Is the cam timing something that would be checked with a timing belt service? I had timing belt done about 1-2 years ago.

I think my father in law has a fuel pressure gauge, so I could check it if need be, but I'll try the other things you said too.

So far the light hasn't flashed since the day before my first post, so I'm keeping my fingers crossed.

Thanks for your help.