nguyenmonkey

Hello! First off, I'm not very car savvy, so a lot of car speech just flies over my head. I'm trying to better myself and learn as much as I can. Second thing: I'm not really used to using forums of any kind, so I hope I'm posting in the right area.

So I have a 2003 Honda Civic Si with about 187,000 miles on it. I've had it for about 2 years, maybe a little more. I bought this car from my cousin for about $4,000.

To be honest, I should have probably had this problem looked at a lot sooner, so it's my fault. I early on when I first had this car, if my car was parked idle for a long time, maybe a few hours, and then I turn it on and drive about maybe less than a mile, it will stall when I slow down (I think that's the proper term?). When I slow down for a stop light or a stop sign, I will just downshift and apply the brakes as necessary, or sometimes I will just leave it in neutral and brake as necessary. When in neutral, the rpms will drop all the way down to zero, and the battery and oil light come on as red at the same time, exactly as how it looks when I actually stall. The only way I get around this stalling problem is if I downshift and apply a little more gas, the car will kick back on, and no problems, or if I just turn it off and turn it back on.

At first this happened only once a day. Over the course of my 2 years, the frequency has been happening more slightly. As of today, I need to drive about maybe a few miles of having this "stalling" issue before there's no problems and I don't have to worry. It still only happens when my car is parked for a few hours to a whole day. Of course the Check Engine Light is always on, but at random times, it disappears for a while.

So the things I have done to my car for a while now are replace the oil (regular oil check ups?), added new tires, and replaced the brakes. That's really about the only major things I've done to the car.

2 weeks ago, I had a pretty bad gas leak from the fuel pump, so I had to get that fixed asap. They also noticed that my Spark Plugs were ****, so I had them replaced. Then earlier this week, my clutch was acting up and not functioning normally, so I had that fixed. But lately do to all this, I've decided to get serious and start fixing up my car and trying to care of it as best as possible.

So I took my car to Autozone today, and had them use the device to read error codes for the Check Engine light. They say that I'm having Codes P0300 (random misfire), P0301 (Cylinder 1 Misfire), P0303 (Cylinder 3 Misfire) and P0304 (Cylinder 4 Misfire) being read. At the top of the document box, it reads:
Definition: Code P0301 indicates that Cylinder 1 had too many misfires within a predetermined period of time.

The suggested parts that are suggested are the Spark Plug and Ignition Coil. But 2 weeks ago I had the Spark Plugs replaced with brand new ones. Could it be that they are still garbage and that I should take it back? Or could it be that the ignition coils are crap and therefore causes the Spark Plugs to be read as crap? My assumption right now is that it's the ignition coils, but I'm certainly no mechanic.

I tried looking into this online about Ignition Coils (youtube vidoes and Coil prices). So far, it seems not that hard to replace. If it's something so simple that can be easily done, I would prefer not to take it to a mechanic and save as much money as possible. But like I said, I'm no mechanic.

So, in conclusion, can anyone help point me in the right direction as to the best way to go about this?

Very Respectfully,
Vince

ezone

Not sure why the system ghosted your post, but here ya go

They can't diagnose anything, they only sell parts. The only reason they read fault codes is so they can print a shopping list and sell you more parts.


What brand of plugs were installed? Are they correct NGK or Denso plugs, or are they the Botch Platinum disasters from the Zone? Some other random brand? Are they correctly installed? Properly tightened?

Do you know what misfire feels like?
Can you tell if there is misfire while the engine is running?

If any actual miss can be felt then it's likely ignition....but if miss is never actually felt then see below


Between your description of the random stalling and misfire codes that may or may not be felt, I'd say to get the valve clearances checked and adjusted.
Has this job ever been done on this engine?

nguyenmonkey

Hello, thank you for replying to me. Sorry I got back to you so late.

To be honest, I'm not sure which kind of brand the plugs are. The plugs were bought and installed from the same mechanic shop when I took my car in 2 weeks ago to have the fuel pump leak problem fixed.

As for the misfire, I'm actually not sure what it feels like. I know that after my car has been parked for a while, if I turn it on and just have it sit in neutral, in the rpms will dip down and come back up a few times. After that, it will dip and go to zero, turning the engine off, and pretty much make the car stall (if that is the proper term?). Also, it will happen if I drive for a bit, and stop at a stop sign or red light. If I have to go, I will of course shift to 1st gear, but when I let my foot off the clutch and apply the gas, the rpms will go up (by about 200-300 rpms) and then drop very slowly while giving the car gas. If I keep my foot on the gas, the rpms will eventually start rising at a very slow rate, and then eventually rise fast like the normal rate. I have noticed that, instead just applying the gas pedal during the slow rise in in rpms, by putting the clutch in and taking the foot off the gas and then trying to reshift, the car seems to go just fine.

Also, another thing to: when I'm going from about 2nd to 3rd, and sometimes 4th, there's a loud audible pop which sounds like it's coming from the engine. I can only describe it as the sound of a distant gunshot, or like a single pop from a go-kart motor. I do know that when I first got this car, it never made that sound.

As far as I know, valve clearances being checked and adjusted haven't been done on the engine. My cousin was the previous owner, and he said he never had that done. What is the significance of doing that engine job? And is it generally something that a mechanic would do, or the owner?

Given all this, have I described what a misfire is/feels like/sounds? Thank you so much for your input!

Very Respectfully,
Vince

ezone

When the computer sets misfire code(s) did the check engine light flash repeatedly or did it just illuminate steady?


A 'dead miss' is the equivalent of disabling one cylinder so it can't fire or contribute power in any way, the resultant engine vibration and loss of engine power should be very easy to notice. An engine might only exhibit this type of issue during certain load or driving conditions as well, instead of all the time.
Once a person has experienced this a few times it should become much easier to notice.

Partial/random misfires or a weak cylinder (as opposed to 'dead') aren't as easy to identify strictly by feel.

I questioned the valve adjust maintenance because (out of tolerance) can cause both misfire codes and unstable idle along with random stalling.
Of course there are always other possible causes, but if valves have never been serviced it's at least a starting point.

Valve adjust....An experienced DIYer might tackle this, but I don't think it's a task suited to a rookie. I wouldn't trust the task to rookies in any shop either.
Varying RPM, gunshot sounds, loss of power......I'd just about need to experience the issues first-hand.
You say you aren't car savvy so I think it might be better if you have someone very familiar with these cars see and evaluate all of the issues in person.
The SI is not the typical grocery-getter Civic, you may want a specialist who deals with these on a regular basis.

Maybe xriceboyx will read this thread and chime in with info about good dealer techs or top notch Honda specialty shop in your area (LVNV).


HTH