miss fire

[3.8lcoty]

when I unplug cylinder 4 plug from the coil and try to crank my car it will turn over and over and back fire after a second then turn over and over then back fire again.

what could cause this problem

[2.8 Bird]

Re: miss fire

It could be ignition timing related or fuel related.

[3.8lcoty]

Re: miss fire

so maybe injector gone bad because every once in a wile it will run fine with it unplugged, because timing would probably be a constant problem?

[alex553]

Re: miss fire

Why would you unplug it and then crank it?

[Docta]

Re: miss fire

What made you unplug it? Need more info...

[WarShrike]

Re: miss fire

Maintenance needed. When have you last done plugs/wires? Still on original coils/ICM?

[3.8lcoty]

Re: miss fire

Well i had read before you can unplug a wire one at a time and if runs different than something if wrong with that cylinder.but when i first did it to the back coil my miss would stop but now it runs fine on all other plugs un pluged except the number 4

[3.8lcoty]

Re: miss fire

And just got my icm tested new wires coil and plugs

[2.8 Bird]

Re: miss fire

What made you unplug it? Need more info...

It's not a bad thing unplugging it. It will help reveal if the coil or wire are bad.

[3.8lcoty]

Re: miss fire

Any help would be awesome im getting terrible gas millage right now

[Docta]

Re: miss fire

So basically when you unplug cylinder 4 it stays the same? Is that what you're getting at?

The idea behind unplugging a wire is the find which cylinder is missing. But in the days of OBD just go to a parts store and get it scanned. If its missing, it'll set a code.

Each cylinder needs 3 components to fire. Fuel, from and injector, spark from the plug/wire/coil/, and air from the valves/intake. If its missing, its not getting one of those three.

[3.8lcoty]

Re: miss fire

What im saying is when number 4 plug if unplugged and i try to start it it just turns over and back fires

[Docta]

Re: miss fire

Then leave it plugged in? You're not telling us the problem...

[3.8lcoty]

Re: miss fire

Then leave it plugged in? You're not telling us the problem...

that's obvious, what im asking is since it only back fires and will not crank with the number 4 plug un plugged and not when any of the others are individually unplugged, does that mean something is wrong with that cylinder or the parts that help it get air fuel spark. because I am having a constant miss fire and I im trying to find the problem so I didn't know if it was a sign of something wrong with that cylinder.

[Docta]

Re: miss fire

Any check engine light or codes? That's a good place to start.

To check each cylinder, leave the car running and unplug each one at a time. If it changes, its not that cylinder. Go until the miss stays the same, then you know its that cylinder. If none of them do, its fuel or air.