Nicolas

Hi everyone i have a 2000 honda prelude bass and i have been having major missfiring problems and have know idea what the problem is this is a list of things that i have changed so far.

1. distributor cap and rotor
2. spark plugs
3. coil pack
4. distributor
5. 02 sensor- car throw up a code for o2 sensor

when i start the car it runs good but then once the engine worms up it starts to missfire steadily and its a miss fire like i never heard before MY PRELUDE SOUNDS LIKE A SUBARU! the car is not burning oil or coolint out of the exhaust so it cant be the head gasket right? so what could it be? bad ecu? i have no idea if anyone can hear me please help! next thing to do is bring it to the shop and pay a lot of money this all started after i missed a shift at high rpm and over revd my car really bad ever since then the car had this problem and then the problem went away one day and didnt come back for about 2 months if any of you guys or gals have had a problem like this please let me know thanks.

BLACKANESEMAN

sounds like you have a damaged cylinder. I had a similar problem on my civic. sounded like a subaru afterwards and I had less power while driving. I find it weird though that the problem is only there after the car warms up. anyone else care to chime in?

Nicolas

What do you mean by a down cylinder? do you mean like a cylinder is not firing at all or the cylinder its self is damaged some how? rings? sleeve?

MPR

I'd guess you broke a valve. When you pulled out the old spark plugs, I bet one looked a lot different than the others.

Do a compression test. I bet one cylinder will read "0".

Over-revving will cause internal damage, not ignition problems. What I believe happened here is a valve hit one of the pistons and either bent the valve stem or broke the valve.

The reason it sounds like a subaru is because one cylinder is "dead" (not firing) due to lack of compression in that cylinder.

Nicolas

but it only does it when the engine worms up and this will take about 5 mins before the misfiring happens

Nicolas

from what i remember all the plugs looked the same i don't think i broke any internals i think that i have a electrical problem because the car has been misfiring on and off for months. i drove to guelph and back not one problem but the next day the misfiring came back if i broke internal parts in the top end or bottom end the car would run like ---- all the time not just some times and also it would do it when its cold or hot dosnt matter the temp when you have a broken valve you will hear it all the time.

Nicolas

I guess im all on my own with this problem just like most of all my other car problems i dont think that it is a really bad brake like you guys are making it seem im almost 100 percent sure its electrical but i guess we will see when i bring the car in but intill then im going to check out a few more little things that might be the problem like wire or maybe a bad ignition relay. if i win the 11 mill in tonight draw ill just swap in a fresh k24

Nicolas

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MPR

My apologies, I didn't notice where you said it runs fine for a while then starts to misfire once it's warmed up. I thought you had said it runs like this all the time. My bad.

In that case, no I don't think you broke anything internal...

An bad ignition (main) relay would not cause one cylinder to misfire, it would shut off the whole engine.

It's still possible you have done enough damage to one cylinder such that it had reduced compression enough to cause a misfire. You may have a slightly bent valve or scored/chipped piston.

Personally, I'd do a compression test and tell us the results for all 4 cylinders. If that comes back ok, You should also have a leak-down test done, and tell us the results of that as well.

chris_v2

Don't take this the wrong way, but this is the problem with home 'mechanics'. You think you know exactly what's wrong or what you're doing. Listen to the experienced guys on here or the actual licensed techs.

This is what you do, you isolate the cylinder that is misfiring, test spark to it (has to be GOOD strong spark). Then you test to see if the injector is pulsing and firing, if they are both good, now you check compression or better yet, do a leakdown. Compression tests take 2 minutes, sure it doesn't sound like a compression issue, but why are you going to over-look a simple test that may solve your problem? After you eliminate those 3 things, THEN you can assume it's an electrical problem.

This thread is a few weeks old, so I'm sure you already know what the problem is.. my post is more to educate for future searches.

civic_ek96

Always start with spark and fuel i say its bad cps sensor or bad fuel injector