Rep Power: 0

Looking for suggestions to diagnose misfire in my 01 Civic 5 speed which has 169,000 miles. Check engine light came on. Stays on consistently for most of the time but sometimes it also flashes before then again staying on. Took it to autozone and was given troubleshooting codes P0300, P0301, P0303, P0304, P1399. Then dropped it off at the Honda dealer and they reported codes P0301, P0303, P0304. They ran compression test: 1-130# 2-130# 3-60# 4-130#. Then they ran cylinder leakdown test: said that cylinder 3 exhaust valves leaking. Said they don't rebuild engines and said engine needs replaced. Offered me a 110,000 mile used engine for $3498.00 plus tax. Needless to say I paid their $43.00 diagnostic charge and picked up my car. I can believe that the number 3 cylinder exhaust valves need replacing, however, I don't see that as the reason for a random misfire. Can't afford an engine rebuild or replacement and would like to try to fix the misfiring for now and save the engine rebuild/replacement when I have more $ to spend. After getting it home (had good power both on the highway and stop and go driving but RPMs intermittently dropped off at idle so goosed it to insure it wouldn't stall at stop signs) I popped the hood when it was dark to see if I could see any sparks arcing by the ignition wires at idle and saw none. What do you think is the most likely cause of the misfiring and what should I try to replace to see if I can correct this. Also, how do I turn off the check engine light? Thanks for your help!

 
Rep Power: 0

what do the spark plugs look like??? are they wet?? A blown head gasket will leak coolant and wet the spark plugs causing a misfire. A red color in the spark plug is burnt coolant.

 
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Since the Honda dealer did a compression check I assumed they would have noticed any wetness or discoloration and reported it to me. Since they did not say anything about the plugs I assumed they were ok and have not checked them. But you know what they say about assume. I will pull the plugs today and check them. Thanks for responding.

 
Rep Power: 235

Get a second opinion. A burnt valve doesn't mean that you need a new engine, it means you need a new valve if not a new head. You need to check for burnt rings but that's repairable too. With these engines it's usually cheaper to replace the engine than rebuild. If you have to replace the engine find a salvage engine with low miles and have your mechanic replace it. A low mileage engine will cost you $500-1000 and labor usually runs $1500-2000 so the dealer isn't to far off on your estimate although it seems like that's excessive for the mileage on that engine. Try here for salvage listings: http://car-part.com/

 
Rep Power: 0

OK. Pulled the plugs and 1 2 and 4 looked good with tannish gray color. Number 3 was caked with black hard stuff on the firing tip (carbon deposit?) So head gasket is not the problem with misfiring.

 
Rep Power: 0

Still searching for a fix to my misfire. Replaced the autolite plugs with NGK ZFR5F gapped at .044,replaced the fuel filter, and added a pint of Sea Foam injector cleaner to the gas tank. Drove for about 20 miles so far with no noticeable improvement. Any suggestions for a cure will be appreciated.

 
Rep Power: 812

it is rare, but it could be a bad ignition coil. test all four by taking them off and use an ohm meter to measure the resistance. i dont remember which two contacts of the three need to be measured, but keep trying different combinations til you get a reading other than 0. do that for all of them and the readings should be very close to each other. if one is way off, replace it.

 
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Don't know what I was thinking when starting this thread. My Civic is a 2000 not 2001 so it doesn't have 4 ignition coils. Could it still be the coil and if so how can I test it to determine if it is bad? Sorry for the confusion.

 
Rep Power: 812

oh okay for older civic, you have a distributor and a single ignition coil. it can still be the coil (some auto stores have free testing) but can also be a bad plug wire or wrong firing order hookup of the wires from plug to distributor. or the distributor cap/rotor or the whole thing. start with the easy/cheap ones first and see if it helps. you may need a haynes manual for some of it.

 
Rep Power: 0

Have tried a few more fixes to resolve the misfiring. Replaced the ignition rotor and distributor cap. Added a pint of Sea Foam to the gas tank to clean the injectors/fuel system. Sucked another pint of Sea Foam through vacuum hose into the engine (really smokey stuff). Still misfiring. Plan to check fuel pressure next by attaching gauge to the fuel line where the fuel line enters the fuel filter. Is this a good place to connect the pressure gauge?

 
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Checked fuel pressure by attaching pressure gauge to the fuel line where the fuel line enters the fuel filter. This was evidently not a good place to connect the pressure gauge since I initially got a reading of over 60 psi and I understand it should be between 38 and 46. Where should I have attached the pressure gauge to get correct reading? Thanks.

 
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Well, I just threw another $41 part in the mix (coil) to see if that would correct the misfiring. It did not. While the car was running I removed one spark plug wire at a time to see if there was a change in how it ran. Cylinders 1, 2, and 4 pulled wires resulted in car stumbling and almost dying. Cylinder 3 plug removal resulted in no change to how the car was running. This is the cylinder that Honda technician said tested at 60 psi.. My plan now is to pull the head to check for burned exhaust valves in #3 cylinder. Any other suggestions will be appreciated. Thanks.

 
Rep Power: 812

something is wrong with that cylinder then. either bent valves or a small gasket leak maybe. how did it happen? if its a problem with the head, you can usually find a good used one off ebay around $150, then have a machine shop pressure check and prep it for $50 and drop that in. much cheaper than new engine.

 
Rep Power: 0

Pulled the head today. (sure are a lot of hoses and connections to fiddle with just to remove a head.............a lot more involved than with my '66 Austin Healey 3000...........) Everything looked good except for the exhaust valves on #3 cylinder. One was burned very badly with a small v shaped piece missing while the other looked not too bad but had hairline crack on the edge. Ordered two exhaust valves, intake manifold gasket, and head gasket and plan to put it all back together when the parts arrive next week. The head gasket I removed was three separate pieces/layers. Is it necessary to have these three layers? If I only used one layer when installing the new head gasket would this result in a higher compression and more power or would this increase the potential of blowing the new head gasket?

 
Rep Power: 0

Success! Replaced the two exhaust valves in #3 cylinder. Engine light out. Runs great!

 
Rep Power: 812

yay great job man