Need help solving an intermittent miss

[Shadow]

A 4-cylinder engine misfiring is usually pretty obvious. I mean, even one cylinder misfiring is 25% of the cylinders. I think your first step should really be to determine if you actually have a misfire issue or not. You might be chasing a problem that doesn't exist!

[bk7794]

A 4-cylinder engine misfiring is usually pretty obvious. I mean, even one cylinder misfiring is 25% of the cylinders. I think your first step should really be to determine if you actually have a misfire issue or not. You might be chasing a problem that doesn't exist!

Yes, But sometimes its a misfire, I know...and sometimes its feels like a minor hesitation. Like a set back if you will. They vary in intensity.

Sometimes it is an obvious misfire.

And today I shifted and as I let out into second the car seemed to have backfired or something.

Sorry for lack of details..I really am finding it hard to explain this

[theholycow]

I am worried that its my axles aswell...

What makes you think that?

[bk7794]

I am worried that its my axles aswell...

What makes you think that?

I have lateral play on them, I heard from Honda mechanic because I was complaining of a chatter. He said to watch for that.

Ok, I just got home. So I went back the same way I came and I got only 1 miss. I got had none of the hiccuping I guess you could call it. Of course it was about 20 to 30 degrees cooler.

This is making me actually think its the main relay for my fuel pump. But ofcourse I am not 100% sure. I know that the main relay when it is heated up it will cause it not to start. I had that issue before.

[theholycow]

I forgot about that main relay issue. There's plenty of instructions on the web for resoldering it.

The symptom being reduced with lower air temperature is interesting. That leads me back to wondering about timing. Could you be getting some kind of preignition/spark knock? A cooler engine with cooler intake air would damp that symptom. I'm not sure it could manifest the way you describe, though.

It also points to the cooling system, obviously, and that's a system that can be significantly less effective without an obvious failure on an old/high-mileage car. So, how about that cooling system maintenance?

[bk7794]

The gauge says normal. And the whole cooling system minus the water pump and headgasket has been replaced within the last year.

I might recheck my timing. I really think its too advanced/retarded. Not sure which.

[theholycow]

The gauge can only tell you the temperature of your coolant. If your coolant isn't circulating everywhere (blocked passages in engine or head), those places will get too hot. Seems unlikely though.

[bk7794]

The gauge can only tell you the temperature of your coolant. If your coolant isn't circulating everywhere (blocked passages in engine or head), those places will get too hot. Seems unlikely though.

I am going to check the timing sometime today. Once I fix it I am going to see what happens.

EDIT: I guess it didn't happen because it rained out. I did do some research, I guess as electrical components wear they tend to advance the timing a bit...But I checked it a few weeks back and it was all over the place on the crankshaft pulley...but eventually it straightened out on where it needed to be. But I don't think I was standing in the correct spot.

Also I was reading that as the car gets older it may need higher octane due to the carbon that changes the compression ratio. Is that true?

[bk7794]

Alright, I re-did the timing and am soon about to go and get some super high octane fuel to try and dilute the what is rest of the crappy fuel that is in there.

However, this morning I was driving and as I come down this huge hill I kept my foot slightly on the gas. It did a noticeable miss. Come to think of it I usually only get this situation when it is on a hill or under load.

[theholycow]

It does it downhill too?

Which direction did you adjust your timing, advance or retard? Also, have you checked that your timing control system (electronic advance?) is working properly?

Of course the high octane stuff you're about to put in would mask slightly over-advanced timing symptoms.

[bk7794]

It does it downhill too?

Which direction did you adjust your timing, advance or retard? Also, have you checked that your timing control system (electronic advance?) is working properly?

Of course the high octane stuff you're about to put in would mask slightly over-advanced timing symptoms.

I believe I advanced it just a bit. I know timing was not an issue. However I actually marked the mark with white crayon and it was right where it was supposed to be.

I have not checked the timing control system. I will have to see how to do that.

I was reading on all the different types of misfires there are. I wonder if I have a lean misfire

Lean Misfire
The lean misfire is another common reason for an engine "miss"—this is due to an imbalanced air/fuel ratio (too much air/too little fuel). Since an engine needs a richer (more fuel) mixture for a smooth idle, this problem may be more noticeable when the vehicle is idling. The lean misfire may decrease or disappear as the engine speed increases because the efficiency of the volumetric flow into the combustion chambers increases dramatically. This is one reason why a vehicle gets better mileage on the freeway than in the city. An EGR valve that is stuck open, a leaking Intake Manifold Gasket, a defective Mass Air Flow Sensor, a weak or failing fuel pump, or a plugged fuel filter are some of the many causes for a lean misfire.

I noticed on Saturday, when it was hot, if I was driving faster around 70mph to pass someone the missing all went away. I am going to try to get another fuel filter just because its probably something that should be replaced, and all the debris that is probably in the gas I had previously bought probably didn't help.

Again I do thank you very much for all the help you are giving me...I know that some of my responses seem to be all over the place. I apologize for that.

[theholycow]

Lean misfire is certainly a plausible diagnosis, but I would expect a Check Engine Light with codes related to lean mixture (too lean, O2 sensor out of range, etc).

[bk7794]

Lean misfire is certainly a plausible diagnosis, but I would expect a Check Engine Light with codes related to lean mixture (too lean, O2 sensor out of range, etc).

But if fuel was being limited by either a clogged fuel filter then maybe that could be it.

Remember when I said it started higher in the RPMs in third gear? Maybe...just maybe it was the beginning symptoms of a clogged fuel filter.

Does OBD0 even give a CEL for a misfire?

[theholycow]

I found this list of codes:
http://honda-tech.com/showthread.php?t=1901557

It includes "45 Fuel system too rich or lean", codes for O2 sensor, fuel system, and cylinder misfire. I don't know how sensitive it is, though it should be sensitive enough.

[bk7794]

I found this list of codes:
http://honda-tech.com/showthread.php?t=1901557

It includes "45 Fuel system too rich or lean", codes for O2 sensor, fuel system, and cylinder misfire. I don't know how sensitive it is, though it should be sensitive enough.

That is OBD I. I wonder if it is the same. I know I can actually look at the computer and look at the led. I might do that sometime. I am also going to replace the fuel filter I think to take that out of the loop. But I don't want to start throwing parts at it.

The sad thing is that I keep getting high 30s (37-39) generally for gas mileage. But I am wondering if it should be slightly higher. Not sure.