Misfire problem

[3800SoloWing]

Well, I think i might have something major going on. I think either a spark plug is bad, or the engine's electronics screwed up. The engine misfires under acceleration, and I can almost concur that its in only 1 cylinder. Its an irregular misfire, in which it wont do it unless the throttle is half way down. Also, even though I know its there, the engine's self diagnostic system wont pick it up; well, it did for a day, then it shut itself off and it hasn't come back on since. The way it sounds and looks as well as what my mechanic told me, the electronics board has gone bad, and needs replacing. Thats the ENTIRE electrical system in the car front to back. I b.s. it because this was the mechanic that nearly cost me the engine because he didn't flush the coolant correctly AND mixed Dextron with that green coolant and corroded the thermostat shut. I have since fixed the thermostat and properly flushed the engine myself, getting the corrosion out, but it wasnt until recently that the misfire started happening. It starts up just fine, cruises perfect, runs strong, but when you push the throttle about half way down, one cylinder misfires.

Do help, I refuse to go back to that mechanic after he nearly screwed me completely over...

[Mogobs30th]

Re: Misfire problem

Well, I think i might have something major going on. I think either a spark plug is bad, or the engine's electronics screwed up. The engine misfires under acceleration, and I can almost concur that its in only 1 cylinder. Its an irregular misfire, in which it wont do it unless the throttle is half way down. Also, even though I know its there, the engine's self diagnostic system wont pick it up; well, it did for a day, then it shut itself off and it hasn't come back on since. The way it sounds and looks as well as what my mechanic told me, the electronics board has gone bad, and needs replacing. Thats the ENTIRE electrical system in the car front to back. I b.s. it because this was the mechanic that nearly cost me the engine because he didn't flush the coolant correctly AND mixed Dextron with that green coolant and corroded the thermostat shut. I have since fixed the thermostat and properly flushed the engine myself, getting the corrosion out, but it wasnt until recently that the misfire started happening. It starts up just fine, cruises perfect, runs strong, but when you push the throttle about half way down, one cylinder misfires.

Do help, I refuse to go back to that mechanic after he nearly screwed me completely over...

That mechanic should be working at McDonalds.

Do you have an SES (Service Engine Soon) light coming on?

[3800SoloWing]

Re: Misfire problem

At one point, yes. But a day later the light turned off and the problem still existed.

[Taheen]

Re: Misfire problem

I was having a misfire myself for the past few weeks. Only happened under part throttle, seemed to have more to do with the load. Low rpm was fine.. push throttle and misfire. High rpm fine.. push throttle and misfire.

Kinda sounds like yours... For me the SES light didn't go on for the longest time, when it did it was a Cyl 5 misfire. Replaced the coils and that was it.

[RadRacer]

Re: Misfire problem

Go get it scanned. Even though the SES light isn't on, it's probably stored in history from when it was on. That'll atleast give us an idea as to what's wrong. And he may have meant just the ICM board needed replacing, not the whole electronics system. What have you done to try and cure the problem? As usual, start with plugs and wires, if that doesn't fix it, then move onto coils. Still no go, then the ICM board. Still doing it, then you may have a serious problem on your hands. First thing's first though; get it scanned.

[3800SoloWing]

Re: Misfire problem

Got it scanned when it came on, and it confirmed the misfire, BUT it didnt tell which cylinder. It might be time for a tune up anyhow, so the sparks and wires come out first...but first I need money...

[Mogobs30th]

Re: Misfire problem

Got it scanned when it came on, and it confirmed the misfire, BUT it didnt tell which cylinder. It might be time for a tune up anyhow, so the sparks and wires come out first...but first I need money...

Don't worry about which cylinder it is. This isnt an older carbeurated car, that misfire could come from MANY sources. Its a bad idea to start throwing money at a problem that you aren't quite sure what it is. Misfires tend to be the most generalized problems with newer cars

Have it scanned again, ask them what the P code is. Once you know the EXACT problem, go from there. Post the P code on here, and im sure we can figure it out.

[Disruptore4]

Re: Misfire problem

Fellas.... mine was doing the EXACT same thing your car is doing. Change the plugs, wires and coils and call it a day. With my car, one of the coils was cracked, and the misfire went away for a while, until I washed my car one day. Some water got into the crack, and the misfire was right back again. Trust me, change the coils, plugs, and wires, and consider it a tune up as well as a repair.

[nightrider2]

Re: Misfire problem

could be a random multiple which could be from a bad fuel filter

[Mogobs30th]

Re: Misfire problem

Guys guys guys.....wait. Its NOT WORTH throwing money at the problem without first knowing exactly what it is. I have had a random misfire before, changed plugs, wires, coils, ICM, STILL didn't fix it. BEST thing he can do is to find what the P code is first, see WHAT the misfire is coming from, or what errors the PCM is throwing out, THEN chase it from there.

You're going to save money down the long road if you aren't throwing money at a mysterious problem.

Fellas.... mine was doing the EXACT same thing your car is doing. Change the plugs, wires and coils and call it a day.

Not cost effective if you ask me. You're talking about $160-$200 in parts if you aren't careful, and STILL not fix the problem.

My advice, GET THE P CODE, post it on here, and we all can go from there.