Cylinder 4 misfiring. Cause of it? [Archive] - GrandAmGT.com Forum

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cfultz10
06-10-2012, 03:53 PM
Okay so here's the story. I'm not very car savvy so i'm just gonna start from the beginning. I was driving to work, stopped at a stop sign, and as I started driving, my Service Engine light came on and my car sounded really boggy. I thought it was something with my exhuast because last year someone stole my catalytic converter and so my very very smart dealer (sarcasm) decided to put a straight pipe on it. I bought the car as is so its not under warranty.

So thinking it was something with the exhaust, I took it to an exhaust shop and they said nothing was wrong with the exhaust itself but my cylinder 4 was misfiring. After asking what could fix it, he told me that changing the spark plug and wire would be good. I did that, I changed 2,4, and 6. (Haven't got to the back ones yet) But it still sounded the same. After looking around on here, i kept seeing that the coil pack should be changed. But I also keep seeing other causes too.

I guess my questions are, how hard are coil packs to change? What are usually the costs? And the biggest question is, what else could it be? Remember, I know a lil bit about cars, but not that much haha

[ChaosweaveR]
06-10-2012, 06:20 PM
The coil packs are simple to change, but change the plugs and wires in the process.

BUT, have a compression check done on cylinder 4, you may have a valve issue. I've seen 03's break lifter bolts, and the intake valve sticks shut, and misfires.

cfultz10
06-10-2012, 09:24 PM
this might sound dumb, but where do you go to get compression checks? or it is something I have to do myself? I'm to the point now where I'm just gonna take it to a mechanic and let them work on it.

[ChaosweaveR]
06-10-2012, 09:38 PM
this might sound dumb, but where do you go to get compression checks? or it is something I have to do myself? I'm to the point now where I'm just gonna take it to a mechanic and let them work on it.

You need a special tool to check for compression, if you don't know what to do, don't do it. If it is a broken lifter bolt, it may get pricey. It's happened to me twice already, cylinder #1 & 3, the broken bolt has to be honed out, and rethreaded. They're aluminum heads, so most shops might not even want to mess with that and might try and throw a remanufactured cylinder head on there.

This may not even be an issue, and it genuinely may only be the ignition causing the misfire (bad coil, wires or plugs) Just throwing out a possibility that's already happened to me. When replacing the plugs, use only NGK or AC Delco iridium plugs.

shiwnath
06-10-2012, 10:07 PM
;1179713']When replacing the plugs, use only NGK or AC Delco iridium plugs.

You can't stress this enough. If you install bosch spark plugs into these engines, it may run fine for a little bit, but it'll misfire like crazy after a couple months.

Also, don't rule out the possibility of a faulty injector. I've never experienced one, but I'd assume it would cause somewhat similar symptoms that as a spark related issue would produce, but again I'm not an expert on this issue.

Also ignition coils are easy to change.

1.)Disconnect the spark plug wires
2.)Disconnect the 3 electrical plugs connected to the ignition coil module
3.)[OPTIONAL] Remove the 2 bolts(front) and 2 nuts(rear) that secure the ignition coil module to the engine. I only mention this because it may make removal/installation of the coil packs on the module a little bit easier and it's not that hard to do
4.)There are 2 smaller bolts holding each coil back in place which need to be removed.
5.) Once the 2 bolts are removed the coil pack should come right off.

Installation is reverse of removal. Also don't forget to apply dielectric grease to the terminals in order to prevent corrosion!

cfultz10
06-12-2012, 09:50 PM
okay so I changed the coil pack for the 2nd and 4th spark plug. Nothing. It said cylinder 4 was still misfiring and while sitting in idle, it even died. Any suggestions? this guy said that the injector might need changed.

cfultz10
06-30-2012, 11:53 PM
turns out it was the rocker arm that came off.

[ChaosweaveR]
07-01-2012, 05:28 AM
turns out it was the rocker arm that came off.

Dafuq? I've seen those let go from over-revving...

cfultz10
07-01-2012, 10:27 AM
I never really revved it, atleast to that extent. Turns out the dumba**es who worked on my car when my converter got stolen, tightened the bolts so tight that it didnt take much.