crk112

This is a random misfire (P0300) on cylinders 1 (P0301), 2 (P0302), and 3 (P0303). You say it only happens at low rpm and at idle... not while accelerating or at cruise.

Dirty fuel injectors could be causing your problems and if so this will clear them up. It's the easiest and cheapest troubleshooting step.. Get $15 bucks and go to O'Reilly's, buy LUCAS brand OCTANE BOOSTER in the red bottle, fill up your gas tank, and pour the LUCAS in (all of it). Yes it says "not street legal" on the back.. not sure why.

If there's NO CHANGE by the time your tank is empty let me know.

If you'd rather try something else get a can of SEA FOAM instead for about the same price.

Curtis

P.S. Happy Thanksgiving

Nrad

I have a 1999 Honda Civic DX Value, 4-Cyl. I had the same problems of rough idle after startup, but runs smooth when I give it the gas. I changed plugs, wires, distributor cap and rotor. It made the engine run a lot smoother. However the CEL stayed on. I had the codes P0300, P0302, P0303, P0304, P1399(random cylinder misfires). I also had the code P0133 (slow response on PO2 sensor.) I mentioned it to my parts man at Honda, and he knew IMMEDIATELY what it was: a CRACKED exhaust manifold. Sure enough, I removed the heat shield, and there was a 2" crack in the manifold starting at the Oxygen sensor and going up!!

Now I just have to figure out how to remove the rusty bolts at the bottom of the EM/Catalytic converter!!

crk112

Good catch with the cracked manifold! When I did my rebuild in April I found that my manifold had cracked as well...

We had to use a blowtorch to heat up those rusty exhaust bolts in order to get them loose.

Curtis

Nrad

While getting ready to replace the Exhaust Manifold, I put a bottle of the Lucas Octane Booster in the tank. After about 50 miles the CEL went out!! I am still proceeding with replacing the exhaust manifold. However, the combination of tune-up parts and Lucas cleared up the large set of codes. Thanks to Curtis (crk112) for his suggestion on the Lucas for the injectors!

Nrad

The CEL returned, with the same codes, minus the P0133. So fixing the exhaust manifold only removed one of the codes. The Honda shop tested the engine. Problem was a leaky head gasget. But it took them hours to find the problem. The engine showed normal compression (145 to 155 in each cylinder), but there is a slow leak of coolant into the cylinders. Also, the cooling system gets pressurized from the exhaust gasses :-) Anitfreeze in the cylinders explains why the engine runs rough at startup.

Since the head gasget is leaking AF, but not enough to show white smoke in the exhaust, could a retorque of the head bolts help in the short term??? Engine has 149K on it.

PhillyTurboSix

Wild thread here and I'm glad to see you guys are keeping up on it and posting results and such. There is truly some great stuff in this thread. Gotta love the power of the internet! Took me a while to read it all that's for sure but it was a good read!

Seems this is a issue with these cars for sure! To give you guys some back round on my misfire issue is, I have a 97 Accord EX with 160K on it. A few years ago the CEL would come on and I had these misfire codes. In all cases I would be going down the highway with he cruise control on about 65mph and the light would just pop on. I'd clear it and it would go away for awhile and come back. I did plugs, wires, cap, rotor, filters, pcv, and all the other tune up things you would typically do. I got all the parts from Honda. I heard Honda parts are the only way to go on these cars as most of the aftermarket stuff is junk. Kinda makes me wonder how many guys in this thread used OEM Honda parts or aftermarket parts when they did their tune ups to help with this issue and if that alone made any difference. So after I tuned it all up the misfire CEL went away for over a year and a half if not more. Just the other day I was on the highway and it went off again. So I'm going to try that octane booster you guys talk about. I typically try to run some sort of injector cleaner 2 times a year just to run it thru the system as it's good practice keeping any engine running good. So add me to the pile of misfire CEL Honda's and I'll keep watching!

PhillyTurboSix

Just for the thread my codes this last time out were...
P0301
P0302
P1300
P1399

Another interesting thing I just thought of the other day my son got in the car and almost had it wot when he started it so the rpm went up for a quick second and he turned it off. Hoping my new misfire codes don't mean the bent valve issue that's for sure!

lsburden

did you replace spark plug wires?
that's what worked for me.

crk112

Hi all;

Shortly after I vouched for the Lucas fuel injector cleaner, I discovered the real reason for my misfires.... turns out I had a broken piston ring on cylinder 3.

Guess I'm tearing down the engine again!!

Curtis

Nrad

Its not pretty when there are multiple problems. My 4-cyl Honda engine codes were ultimately cured by: (1) replace cracked exhaust manifold (2)replace head gasget, with a valve job for good measure while the head was out.

Now the valves are noisy, but the mechanic says the valve clearances are all fine. But the CEL codes are ALL gone, and so is all the money in my wallet :-(

want2na

iTrader: (1)

Crazy miss fire wow

WetEars

Continue the crazy misfire problem…
I have a 1999 Honda Civic EX, D16Y8 motor. 194,000 miles

I have had the P1399 and P0301 error code come up a few months ago. I changed; cap, rotor, plugs, and wires and the problem went away for a month. The code would come up again while at idle then while driving a lot of highway miles the CEL would then go off.
Fast forward a few months, I have P1399, P0300, P0301, P0303. A little history, I had my IACV clogged up about a year ago, I cleaned it and it worked fine then. Also, when I started getting the CEL again (where I am now) I was looking over my plug wires and noticed that the timing for #1 and I think #3 were in the wrong position. I am pretty sure I did one for one swap like 100k miles ago, but not sure. Well it ran fine for a while like that, I’m not sure how. Could this mistake have caused other damage, e.g. carbon buildup, or pre detonation and ruin my valve seats?? Any how I still have this problem and… So far I have:
-Checked for any possible air leaks… nothing noted
-Checked Coolant temp sensor (Ohm check good, changed anyway)
-Checked TPS (volt check good)
-Checked Crank position sensor (Ohm check good, changed anyway with used one)
-Checked fuel pressure test (Actron CP7838 tester) about 2 psi under normal, don’t know if it is a problem with the $45 tester or not. Did this check again after new Fram fuel filter and Delphi fuel pump(FE0169)… same results.
-Checked fuel pressure regulator (drops 10 pressure as designed w/ vac tube on)
-Checked the coil (ohm check good, changed anyway)
-Checked spark (good), pulled wires while running and results in poor idle for each cyl
-Checked each injector plug by pulling it while running, results in poor idle for each cylinder also.
-Checked each injector plug with LED (all operational)
-Checked each fuel injector, all 13 ohms, then checked operation with engine off and applying power, fuel pressure dropped evenly for each injector
-Checked compression dry #1 180psi #2 165 psi #3 165psi #4 180 psi (10 cranks)
-Checked psi for 2 min after compression check, each cyl holds pressure
-Checked timing with SRS jumper wire in place, on red mark
-Checked VTEC solenoid (ohm check and operation good) changed anyway
-Checked speed sensor, 0-5 volts cycled on and off with tire rotating
-Checked PCV and it works now after I changed it
-Checked catalytic converter, no crud of buildup at all and I can see through it fine
-Checked my valve clearance a few times. I recently gave my valves extra clearance to the point it’s ticking .010 intake .012 exhaust. I will move back to spec Intake .008 and Exhaust .010.

What I have done, and what I have changed:
-Ran SeaFoam (2x) and Lucas Fuel Injector Cleaner (no help)
-Sparkplugs -> NGK
-Changed cap and plug wires -> Honda OEM
-Changed Fuel filter -> Fram
-Changed fuel pump -> Delphi FE0169
-MAP sensor from junkyard
-Changed both O2 sensors
-New battery (this helped the most, but problem came back)
-Changed PCV
-Changed VTEC solenoid (still operational)
-Changed timing belt and water pump
-Changed #1 cyl fuel injector (no change and all are working fine I think)
-Changed intake manifold gasket for tight seal
-Changed knock sensor (broke doing intake gasket $140 mistake)
-Cleaned IACV
-Looked for intake leaks all round manifold and hoses using brake cleaner and nothing was found. I think I hear a leak around IACV but not sure and does not change idle when I spar cleaner around it.
-Swapped distributor with one from Honda dismantler and same problem existed
-Even changed the EVAP control solenoid, thought maybe the vacuum leak could be from there, but there was not.

So what I am seeing/feeling… with the valves where they should be and everything together I hear the problem through the tail pipe, I hear a sputter every second or two, like it misfires every few rpm. The misfire adjusts to more every few rpm then less, like the fuel is being trimmed to try compensating. I can also feel the engine running rough and shaking through the steering wheel. Both of these happen more when the car is warm. The misfire cannot be felt when on the freeway, and it seems to be fine one the freeway, and NO loss in MPG either.
Also, after I shut the car off and take it out again when cold I feel the motor bog down and drop in RPM two times, but that is it then it clears up, I know that is odd but what I have noticed. Like the motor is being flooded or something. I push in the clutch and reaved it up a few times just fine. The bogging down is only two times and mostly when the car is not at running temp yet.

I am using a cheap little OBDII MaxiScan MS300 tool to read my codes, and clear them after I attempt to fix the problem. The same CEL codes coming up. I’m not sure where I should go from here. I don’t want to put ideas out there and lead everyone in a direction, but could it be possible my head is cracked even though I don’t lose compression. Or could the problem be that my valves are not seating all the way? Could the problem be from having the wrong firing order for a while and resulting in the head, or valves being damaged? I am bout to change the head out if it might be damaged. I want to avoid having to send mine to a machine shop and costing me $300 vs. $100 for a good used head. Please let me know what you think I should do next, thank you much.

crk112

Hey there;

I think those numbers are ideal... you couldn't ask for much better compression on a (stock) Civic engine. I was getting 180 per cylinder on the fresh rebuild with new valves and rings. The other good sign is that all four numbers are close to one another so you have consistently good compression across all four cylinders.

With that said... you'll might get lucky and avoid having to tear down your engine. Obviously you're making good compression so that's not the cause of your misfire.

The downside is that doesn't leave us with much clue of what the problem IS. You've gone through and done a lot of stuff that I would have done also to diagnose..

You mentioned a new battery made the most improvement out of everything you tried. I wonder if the problem is electrical in nature.. i.e. occasional bad spark. That seems to fit the symptoms you describe. Just to confirm.. you changed distributor, cap, rotor, plug wires, and plugs so all are new? Did you happen to do the ignition coil module? It's buried deep in the distributor. I had problems last year with my ICM where my engine would actually DIE while I was driving on the highway. If your tach needle jumps around when you are hearing the misfire, that is a big clue since the tach runs off the ICM pulses.

Also to check might be the voltages on the wires going to the ICM. I have those specs in the Civic service book but give me a day or two to locate it.

Curtis

P.S. I also made the $140 knock sensor mistake ....

AcuraAdvisor

AcuraAdvisor

I had these exact codes pop up after "testing" a code scanner I bought at a pawn shop. My 1997 acura rl had no engine light prior to plugging in this scanner. I cleared the codes and they would reset within 30 seconds of running and would flash intmt. my engine was not missing (no shake,no vibration,exhaust was not rich ect.)

I thought the scanner killed my pcm/ecu. My shop foreman finally determined that my missfire detection module might have died. I borrowed one from another car to test, after 100 miles no light! everythings happy again. for those of you still chasing this you may want to try this. It fixed mine ! Borrow one from another car to test, these are expensive (400.00) The scanners will not point to this part specificaly, in my case 1301,1302,1303,1300,1399

hotrodjunky420

Ok... first, what is a cel? Its considered the (mil) malfunction indicater lamp.
A 1399 is usually a valve clearance problem. Timing could be a issue, timing belt may have slipped. Basicly when the valve cover is removed, you will check valve clearance and timing marks on belt. intake is .003 to .005 and exhaust is .006 to .008. If there to tight thats your problem. if timing and clearance is fine and all the ignition components have been replaced then you head to fuel. checking with timing light is ignition timing not valve timing. couldve burnt a valve driving with crossed wires.

el crapitan

a 1399 or a 0300 for that matter, could be anything that is common to all cylinders. fuel, ignition, ignition timing, vacuum leaks or low engine vacuum. those are the most common causes.
valve clearance would be pretty low on my list. as it is not usually common to all cylinders. a specific cylinder misfire, sure. but not random.

Ryan96GSR

Threw a p0303, p0301, p1300 and p1399 last night while I was out with the lady. Going to check the timing tonight. Replaced these parts a couple months ago when I bought it; new plugs, wires, cap, rotor, fuel filter. When I pulled the old plugs they looked okay but I replaced them anyways.

The car feels down on power, so my guess is that the belt slipped. Going to start saving my pennies for a swap.

hotrodjunky420

If you look up a p1399,this is with misfire codes.. 300.301.302.303.304.1399.. not a 1300. if you look up 1399 on alldata it says its a manufacturer code for a stuck egr valve or clogged or its a valve adjustment problem.. im not saying it could be something else. the 1.8 and 2.0 dont have egrs so i went over the valves and checked the timing belt marks. ive fixed 3 crv's in the past two weeks and they run like a top.. soooo what can i say.

el crapitan

well, yea. if we're talking about a 97-01 crv that's misfiring. that's the first place i'd check too!

lazaidus

Hey all i have a 98 accord ex 3.0 v6. Been dealing with this code for about a month now(p1399, 303). Ive ended up changing distributor cap, rotor, all motor and tranny mounts, valve cover gaskets, pcv valve, spark plugs, wires, egr valve, egr ports cleaned as well as intake manifold and gaskets replaced in throttle body and intake plenum......this has not helped......the car runs like a champ only a slight vibration at idle. I have thrown so much money into this car that it's crazy......anyone figured out anything? Now im throwing 1399,303,304,300 instead of just the 1399, 300.....

el crapitan

have you checked fuel pressure?

joshheck

Unplug the egr valve I bet all misfires go away the electronics in it may not be bad but it could be gummed up with carbon causing it not to function properly causing a stumble at part throttle under 3000 rpm and throwing multiple misfire codes

Krazy613

I had the same codes and changed the spark plugs (ngk double platinum) and wires (ngk) and runs great now. I do get my 02 sensor code come on again every now and then but I'm sure that a different problem just the o2 it's self going bad 330,555km later lol
Just put this in to say plugs and wires worked great for me . 2000 integra ls b18b1

k3ntegra

Yeah, fuel injectors were the culprit for my car's P1399 code, as well.

Thankfully the CEL came on after I changed the spark plugs and spark plug wires, distributor (entire unit), pcv valve. and shortly before & after replacing O2 sensor.