uhhkilleez

Today I turned on my car and the check engine light was on. It drove fine yesterday and every day before this. There was no cel until I turned the car on today. I drove to VatoZone and had them read the codes which were P0302-72 and P0304-74 so cylinders #2 and #4 are misfiring. The car starts fine, idles fine, accelerates fine, and cruises fine. If the cel wasn't on then I wouldn't think anything was wrong with the car.

I changed my brake pads last night and the last time I did anything really was an oil change about a month ago. I get gas from a Marathon next door to my work, been filling up there for a couple months now.

What could be the cause of the misfires and how can I fix it? I was told to start with plugs and then wires.

Car is a 2002 Accord V6

Thanks

Lost Again

Don't think the 02 v6 has wires (COP setup), too tired to look. Yes if plugs are due that is a good place to start.

Bad_dude

Pull the wires and check more rust which means moisture got in to cause the misfires. Check wires for connections. Pull the plugs and check for worn and conditions.

uhhkilleez

I went and picked up some NGK iridium plugs and had them read the code again. Yesterday was only cylinders 2 and 4 misfiring, but today it was cylinders 4, 5, and 6 with a random misfire code, but no cylinder 2 misfire.
Also, when I change the plugs, if that's what was causing the misfire, will the cel turn off or does it need to be reset?

uhhkilleez

Put all six plugs in, check engine light was still on, took it to VatoZone to have the codes read, was still reading cylinders #4, #5, #6, and random misfire. Actually had to go to three stores because the first two said it was too late and they were behind on their work but it was only 8:00 pm.
Would it be safe to drive like this if I take it easy? I have to work at 4:00pm tomorrow(Wednesday), Friday, and Saturday, and I'm a pizza delivery driver so I kind of have to drive. I'll probably drive around 100 miles this week.

uhhkilleez

I was doing some research and it said a vacuum leak could also be the cause of misfires. I noticed that occasionally when I'm driving I hear a slight whistle noise when I accelerate. Could that be something else to look into?

Forgot to mention the car has almost 214,500mi if that matters.

uhhkilleez

Today I might have fixed the problem, which was really dumb. I got off work and went next door to fill up my tank. I bought a bottle of STP super concentrated fuel injector cleaner and poured it in right before filling it with gas. Tightened the gas cap and started the engine. No check engine light! As I was filling it up it occurred to me that I might not have tightened the gas cap enough last time I filled up. Right on the cap it says "Click at least 3 times or check engine light might turn on"
I think I might have it scanned for codes again tomorrow just to be sure.

uhhkilleez

Is there anybody that can point me in the right direction??

Even bigger problems. So the car is running fine, the check engine light went out. I took it back to have the codes read just in case. Same codes as before, random misfire and misfires in cylinders 4,5, and six, but now cylinder 1 is misfiring as well as reduced fuel economy. I filled it up last night (17 gallon tank) and now it's at just under 3/4 of a tank and I only drove 60 city miles conservatively.
Somebody please help me I want to get this fixed quick before I have to spend a ton of money.

accordmatt

compression check,vac lines im having similar issue but only #1 and i have 4cylinder. when l get up to speed it fires but when l slow down wants to stall

uhhkilleez

How do I do a compression check?

Sometimes at lower speeds and lower rpms when lightly accelerating I hear a slight whistle but I checked for vacuum leaks and found nothing. I really never felt it misfire or felt a loss of power.

The only thing is that the fuel economy seems to be a little lower.
I drove just under 200 miles and it's at about half way between a quarter and half a tank. I'll fill it up tomorrow before work and figure out exactly how much gas I used.

Also, why would it still throw codes even without a check engine light?

accordmatt

CEL light is a endicator of immediate attention. codes are just being thrown when a problem acurse while driving. theres many sensors on all vehices fuel,brakes,ignition,timing.etc so a code with be thrown in any of these cases.

Compression test it a gauge u hook to spark tubes like plug with a tube and PSI gauge u manually crank motor over few times or disconnect distributor harness and try to crank over few times should be around 180-200 psi on all. if not then u have a bigger issue. bad piston rings/burnt or bent valve/stuck valve etc

uhhkilleez

Alright I'll try it as soon as I can.
Thanks for your help

aredden

I had similar issues due to bad gas, but it got a lot worse. If you are confident enough to do this I took off the fuel rail, cleaned it out, checked the injectors(they weren't that bad, I just cleaned them up a bit) and replaced the fuel filter. The only thing you would have to buy to do that is the fuel filter, which is cheap. Mine's been running fine ever since and I have about the same mileage. It's cheap and worth a shot.

uhhkilleez

I think I might do that as soon as I can get enough time to do it.
The cel came back on and another thing is the TCS light comes on whenever I have to do a cold start in the morning and won't turn off with the button but once it's warmed up if I turn it off and start it again the tcs light turns off. I have no idea what that means.