occasional cylinder misfire

any input would be highly appreciated.

i have a 99 prelude with 120K miles and here's where im at:

-the check engine light came on, misfire cylinder #1
-i changed the spark plugs and reset the code
-a week later the check engine light comes on again, misfire on same cylinder
-i changes the spark plug wires and reset
-5 days later the check engine light comes on again, same cylinder #1

i do feel the misfire, like the engine stumbles a bit, and it only happens when the engine is coasting below 2000 rpm, i called a number of shops and suggestions range from:
-dirty injectors
-do a compression test, may need a valve job
-faulty sensors

if im loosing compression, the check engine light should come on right away right? why does it run ok for a week and then misfire all of a sudden?

if its the injectors, do those fuel injector cleaners really work? or should i take the fuel injectors out and clean them?

thanks everyone

any input would be highly appreciated.

i have a 99 prelude with 120K miles and here's where im at:

-the check engine light came on, misfire cylinder #1
-i changed the spark plugs and reset the code
-a week later the check engine light comes on again, misfire on same cylinder
-i changes the spark plug wires and reset
-5 days later the check engine light comes on again, same cylinder #1

i do feel the misfire, like the engine stumbles a bit, and it only happens when the engine is coasting below 2000 rpm, i called a number of shops and suggestions range from:
-dirty injectors
-do a compression test, may need a valve job
-faulty sensors

if im loosing compression, the check engine light should come on right away right? why does it run ok for a week and then misfire all of a sudden?

if its the injectors, do those fuel injector cleaners really work? or should i take the fuel injectors out and clean them?

thanks everyone
EVEN THOUGH YOU REPLACED THE SPARKPLUGS AND WIRES, THE MISFIRE CODE IS STILL ON YOUR COMPUTER MEMORY. IT REQUIRES 80 WARM-UP CYCLES WITHOUT MISFIRE RE-OCCURRING TO CLEAR THIS CODE.

BUT YEAH CHECK YOUR COMPRESSION PRESSURE ON ALL CYLINDERS AND MAKE SURE THEYRE NO MORE THAN 20PSI DIFFERENCE. CHECK INJECTORS AND SENSORS WIRING HARNESS FOR OPEN, SHORT AND GROUNDED CIRCUIT.

any input would be highly appreciated.

i have a 99 prelude with 120K miles and here's where im at:

-the check engine light came on, misfire cylinder #1
-i changed the spark plugs and reset the code
-a week later the check engine light comes on again, misfire on same cylinder
-i changes the spark plug wires and reset
-5 days later the check engine light comes on again, same cylinder #1

i do feel the misfire, like the engine stumbles a bit, and it only happens when the engine is coasting below 2000 rpm, i called a number of shops and suggestions range from:
-dirty injectors
-do a compression test, may need a valve job
-faulty sensors

if im loosing compression, the check engine light should come on right away right? why does it run ok for a week and then misfire all of a sudden?

if its the injectors, do those fuel injector cleaners really work? or should i take the fuel injectors out and clean them?

thanks everyone

I would also check your CAP and ROTOR... perhaps the plug contact point for the number 1 is in need of some scrubbin.

40 warm up cycles with out a misfire to clear it, or have an autoparts store clear it, yes some fuel injectors cleaners work buy one and pour it in your tank with a full tank of gas... next time it starts to misfire use a stethoscope to make sure the fuel injector is firing it could be a bad fuel injector.. and do check or replace your cap and rotor...



gunnmen01

thanks for the help guys, but still no go.

- i replaced the cap and rotor, there was some corrosion in there
- i reset the computer (pulled out the radio fuse for 10 sec)
- CEL came back on after 2 days, misfire cylinder 1
- i replaced the spark plugs again with Original Equipment NGK platinums.
- reset the computer
- CEL came back on after a day, misfire cylinder 1

any ideas?

i also put in 2 bottles of Fuel Injector cleaners, in case the injector was dirty, ran that tank thru and still getting the misfires.

help....

i also put in 2 bottles of Fuel Injector cleaners, in case the injector was dirty, ran that tank thru and still getting the misfires.

help....

might seem a lil obvious - but have you also been setting your timing thru-out all this ? (with the service connector jumped as well)... also try removing the injectors completely and having a look at the nozzle end - spray some carb cleaner or something on them.

best of luck - let us know what works (;

perhaps it's also your internal coil or something... not to familiar with 97+ myself (:

When mine was studering and misfiring it turned out to be the MAP sensor. I took it to a shop to check for this. None of the codes pointed to this problem but they did some trouble shooting using a shop manual and found out it was the culprit. It's only about $75 although they had to go through a parts supplier because the dealership claimed to have discontinued the part.

i am having the exact same problem as you. i'm talking about, 100% exact. i've gotten the same responses from friends and mechanics, replaced cap and rotor, wires, plugs, and fuel injector cleaner helps alot, i haven't gotten the chance to pull the injectors, or the money to replace them, but thats probably the culprit. if you figure it out, let me know, if you figure it out, let me know :)

thanks for the reply folks... ludeguy, thanks for the input, and yes, i have been setting my timing after i reset my computer.

ok, i did a compression test just to make sure and all 4 cylinders came back at 180 ~185 psi (big sigh of relief), so its not my valves or any leaks.

hey, crzyCollegeKid, how many miles do you have on yours, mine has 130,000 miles and im wondering if this is a common thing with high milage preludes...

anyways, so i pull out my injectors, scrubbed them clean with a can of carburator cleaner and swapped the injectors on 1 and 2 (it was fairly easy, took an hour or so)... the misfire came back but this time it was on cylinder #2... i think i have found my culprit....

i know the injector isn't completely bad, coz i don't notice any loss of HP and fuel efficiency... but i have put in 2 bottles of those fuel injector cleaners...... have any of you guys tried that Injector Cleaning service that shops offer for $70~? do you think this will help my cause?

my lude has 109.3k miles on it
when i get a chance, i'll try the injector swap, its probably bad

if you do, careful when you put the fuel rail back on the injectors, i tore 3 O-ring seals when i forced it in, had to buy replacement O-rings from the honda dealership ($2 each).

the right way to do it is to twist the injectors left to right as you lightly push the fuel rail in, the injectors should slide right back in.

its been a week now since i had the injectors cleaned and no misfires. thanks for all the help guys!

i could've sworn you gave me a link to where you could get the injectors for like $27 each but i can find the post anywhere!

no problem, here it is.

http://fuelinjectorwhse.com/CATFRAMSET.htm

good luck!