Misfire / Rough Idle

[89 FIREBIRD]

do the idle relearn, see if that helps. (i'm not sure 2004 needs it done).

mist your wires and coil pack with water while running and look for a light show. Also verify you put the wires on the plugs all the way and did you gap the plugs?

What is the idle relearn? Having same problems

[JusteR]

I don't mean to beat you up, but I want to understand what is going on...

I dont hear or feel the misfire, but the CEL flashes after about a minute of resetting the code. The engine idles very rough.

Misfire = "runs rough." Light flashing = catalyst damaging misfire.

Since i have changed the Coil, Oxygen sensors, and the fuel filter/pump.

That seems like a lot of money... change the oil too if it smells like gas.

I've had a compression test and the compression is apparently good.

Why do you say "apparently?"

If it were mine, I would be doing a power balance test to isolate which cyl(s) is(are) not contributing. I would check enhanced data for fuel trims and the misfire counters.
I might even inspect the timing belt, roll the engine to TDC and see if the marks line up, then do a cylinder leakage test if I am confident it is a mechanical issue.

If you disconnect that light, another might come on in it's place.

I think it makes more sense to either study and tool up or invest in a trustworthy mechanic. Misfire codes are complex and can be time consuming even if approached systematically. HTHY

[DPjcarsnotok]

I'm actually having a similar problem with my 2005. I haven't gotten a chance to check the plugs, wires, or coil packs yet. What happened to mine has happened gradually, it used to just seem to kind of buck out on the highway if I didn't have the RPMs up high enough and downshifting would seem to clear it up. Now recently it has become a real issue to the point that it has no power out on the highway whatsoever, even the slightest grade bogs it down. It is definitely idling rough, sometimes almost to the point is seems it wants to cut out. The check engine light flashes at first, then will stay solid on for a period of time then will begin flashing again. It's got around 75k and actually recently had the head rebuilt and the timing belt and idler pulley replaced so I doubt it is a compression issue. My biggest concern is that when I got in after work this evening I turned the lights on and the dash was completely dark which kind of makes me concerned there may be a more serious electrical fault at play here as I have observed the dash lights and clock brighten and darken as if maybe there was some sort of power regulation issue (??) Im certainly noe expert so any advice would be appreciated

[Pickles]

I'm actually having a similar problem with my 2005. I haven't gotten a chance to check the plugs, wires, or coil packs yet. What happened to mine has happened gradually, it used to just seem to kind of buck out on the highway if I didn't have the RPMs up high enough and downshifting would seem to clear it up. Now recently it has become a real issue to the point that it has no power out on the highway whatsoever, even the slightest grade bogs it down. It is definitely idling rough, sometimes almost to the point is seems it wants to cut out. The check engine light flashes at first, then will stay solid on for a period of time then will begin flashing again. It's got around 75k and actually recently had the head rebuilt and the timing belt and idler pulley replaced so I doubt it is a compression issue. My biggest concern is that when I got in after work this evening I turned the lights on and the dash was completely dark which kind of makes me concerned there may be a more serious electrical fault at play here as I have observed the dash lights and clock brighten and darken as if maybe there was some sort of power regulation issue (??) Im certainly noe expert so any advice would be appreciated

Sounds like a bad ground to me. Clean your contacts, and check the battery negative to body cable to see if it is corroded

[Pickles]

I'm actually having a similar problem with my 2005. I haven't gotten a chance to check the plugs, wires, or coil packs yet. What happened to mine has happened gradually, it used to just seem to kind of buck out on the highway if I didn't have the RPMs up high enough and downshifting would seem to clear it up. Now recently it has become a real issue to the point that it has no power out on the highway whatsoever, even the slightest grade bogs it down. It is definitely idling rough, sometimes almost to the point is seems it wants to cut out. The check engine light flashes at first, then will stay solid on for a period of time then will begin flashing again. It's got around 75k and actually recently had the head rebuilt and the timing belt and idler pulley replaced so I doubt it is a compression issue. My biggest concern is that when I got in after work this evening I turned the lights on and the dash was completely dark which kind of makes me concerned there may be a more serious electrical fault at play here as I have observed the dash lights and clock brighten and darken as if maybe there was some sort of power regulation issue (??) Im certainly noe expert so any advice would be appreciated

Sounds like a bad ground to me. Clean your contacts, and check the battery negative to body cable to see if it is corroded

[DPjcarsnotok]

Sounds like a bad ground to me. Clean your contacts, and check the battery negative to body cable to see if it is corroded

I checked the battery terminals they are totally clean, I followed the ground cable as far as the starter and it seems to be solid. I don't have time to trace it back to the body as I've got to head out to work momentarily, but it's still wrapped in the factory protective covering (that corrugated tubing wrap they put on it) so if there were a break inside there I can't tell, but that seems unlikely as it seems undamaged and fully intact. I also sprayed down the coil pack to check for the "light show" but saw no apparent sparks. Oh well, I guess I'll be pulling the plugs this afternoon when I get a chance. Thanks

[DPjcarsnotok]

Thanks for the advice regarding the misfiring issue, when I went to pull the plugs there was actually one snapped which of course caused my miss but nothing a new set of NGK iridium plugs couldn't fix. Apparently when the head was replaced the ^%#ing mechanic put the old plugs back in. Oh well, one less mechanic out there that will get my business. Huge relief though, running great now. However the dashboard cluster lights are still out as well as the passenger side front and rear running lights. I checked both fuse panels and the corresponding fuses are intact. In the engine compartment fuse panel there is a long white bar at the extreme right side of the box assuming you were standing looking under the hood. It seems to be some sort of module, don't know for sure what it is, but it is a rectangular white bar that looks as if it snaps into the edge of the panel box with a rectangular indentation that runs along the top side and a cluster of several multicolored wires coming into it from the bottom. The extreme edge of this bar looks as if it has become very hot and brown (smoked) at the top closest to the coolant reservoir at the right edge of the bar. I don't know if this is significant, but any advice would be appreciated.

[Pickles]

If the dash lights, park lights, tail lights, and license plate lights are all out then the circuit isnt getting power. It would be a relay/fuses, or a line to/from the fuse box itself. I would start with the relay since you checked the fuses

[JusteR]

That long thingy is a splice pack. There is one in my 08 sv hb underhood fuse box for several power feeds. also, one behind the IP way up and taped on the body harness for several ground feeds. I took pix on how to access the latter if ne1 is interested.

HTHY.

[JusteR]

Sorry, was out of town again this weekend. The Splice Pack comes apart (unless melted itself together) similar to a connector. Think of it as a terminating connector that joins all the wire terminals together. Splice packs can experience fretting and poor pin tension/contact just like any other harness connector. take one apart if you're bold and curious and you'll see.

On a lighter note, saw 4 Aveos on the way home tonight. A new Record!