2G Missfire on Highway Restart fixes

[mx3baker]

I recently purchased a 96 GSX which may have been a mistake with the issues im having.. If i drive the car on the highway 60mph+ it will throw the P0300 misfire code and act like its running on 2 cylinders. I shut the car off while on highway and start it and the cylinders come back for a short while. I do have the stock CAS.

I have captured some ECMlink logs. The Highway pull shows the missfire towards the end then i shut off the car and turn it back on. The cylinders come back.

 

[mx3baker]

I just traded plug cables around to see if it was a cable ran down the highway. The light popped on and i had some small sputters but it came out of it and ran fine. Is it normal for this thing to get so hot even the hood prob burns your fingers... wow

 

[gofer]

Ok just got done testing the coils and after i found something better to sting down in there to get a good reading they came out reading at 12.4k and 12.6k (good) i took it for another spin to set off the misfire and i shut off each injector in ECMLink with no changes im guessing when the P0300 triggers it will not let you change the injector state. So i pulled ea spark plug cable 4, 3, 2 all made the car sputter worse and i noticed sparking still happening on the spark plug end of the cable. Plug 1 on the other hand when i pull the plug out it arcs AT the coil and does not change the sputtering of the engine. Also if i unplug the injector for 1 it does not sputter any worse like the others do. Now to figure out which part is bad?

The bad part's on cylinder 1, check the resistance across that plug wire (probably wouldn't hurt to check all of them. It should be 22kΩ max per the FSM.

If it checks out fine I'd still swap cylinder 1 plug wire to cylinder 2 or 3 (just not 4) and go for a drive, just don't forget what cylinder you swapped it to, and see if it drops on the cylinder you moved it to.

 

[mx3baker]

I swapped plug wires with plug 3 and it threw the code and stumbled a bit but it came out of it. I think ill run it down the highway again. I was thinking about swapping injectors to another port

 

[gofer]

Hold off on the injectors, you've got to be 100% certain it isn't the plug wire first that's causing it. Just it stumbling/recovering and not throwing the CEL seems like you may have found the issue already. Don't forget to try ohm'ing out the plug wires...

Keep driving it and see if you can duplicate the issue with the cylinder 1 plug wire swapped onto #3 for at least few days. If it doesn't happen after a few days swap the plug wires back to where they were when it was throwing P0300 and drive it.

It's important that you only do one thing at a time using the process of elimination, if you do anything else to it other than the plug wire swap you won't know what did/didn't fix it. The good news is that if you NEED to get to somewhere and not have it leave you on the side of the road you can just eliminate the misfire issue with a click of a box in ECMLink until you have time to troubleshoot it.

 

[mx3baker]

Tested resistance on all plug wires they were all with in spec. I will do some driving with the wires swapped and report back..

 

[mx3baker]

Tested resistance on all plug wires they were all with in spec. I will do some driving with the wires swapped and report back..

I went ahead and ordered some new NGK wires..

 

[mx3baker]

Update after new plugs. I was driving down the highway it seemed to be running great but i had the CEL come on and same #1 injector shut off. It took longer this time but it is the same and when i unplug the plug wire i still get the arc at the coil, From the coil to the screw head closest to it. This tells me i might have a small crack in my coil. Thoughts?

 

[Brembo]

Update after new plugs. I was driving down the highway it seemed to be running great but i had the CEL come on and same #1 injector shut off. It took longer this time but it is the same and when i unplug the plug wire i still get the arc at the coil, From the coil to the screw head closest to it. This tells me i might have a small crack in my coil. Thoughts?

Spray some windex over there and see if it will start arking. Sometimes you can even see it if it is dark enough and look hard enough. Just spray good amount but don't put water hose over there.

 

[gofer]

Mark the #1 plug secondary coil pack with whiteout or a marker and then swap secondary coil packs, see if the cylinder misfire moves with the suspect coil pack. If my memory serves that coil when swapped will go to #3.

 

[mx3baker]

Good idea, and Correct it should go to 3. Now if i can find the easy how to of removing coils...

 

[Brembo]

Easier would be to spray some water on it.

 

[mx3baker]

Easier would be to spray some water on it.

Ok i just tried this i sprayed water on the area and it started arcing at the same spot from the #1 coil to that screw head next to it.

 

[Brembo]

Din din ding. We have a winner. You need coils.

Food for thought: Most newer coil on plug systems you move the coils around and see if you will fry coil drivers in the PCM. If PCM survives then you check if the miss moved. On older cars with wires the water trick is the first thing you do is because water creates a path to ground plus you can see it and hear it. Normally in older cars their is no misfire monitors so their is no guide and that's means you need to identify the actual cylinder yourself.

 

[mx3baker]

Do you see any reason to replace both at the same time?

 

[Brembo]

I think you should do coils and the rest of ignition system. Such as wires and plugs gapped correctly. You won't have to touch it again for a long time. Also use some die electric grease on connections of the wires. If out of the budged then do it in steps but get it done. It's a piace of mind that everything is in working order.

 

[Brembo]

Some people will say oh no this guy recommends to change all of the coils, well yes because they are extremely old and one already failed so the other is not far from it. If the rest of ignition system is fairly new then you can leave it alone. I think you posted that you order the wire and plugs were changed.

 

[mx3baker]

Finally got a new OEM Coil and installed it last night. Took it for a drive down the highway without issue. If i pull Cyl 1 plug the spark continues to travel down the wire instead of arcing at the coil now. Thank you for the help! Now on to the next problem.

 

[mx3baker]

Bad news... The problem happened again today... i did not pull over and check cylinder but i will try to recreate the issue on a less busy highway... For what its worth i could have swore i heard the clicking of spark as if it was arcing somewhere while i was driving...

 

[Macgyver'sDSM]

Are you running a 1g cas by any chance?

 

[mx3baker]

Are you running a 1g cas by any chance?

No, its stock

 

[PrimerPLus]

Heat can change things. I think you said you checked the Power Transfer Unit but I would bet that it's the issue.
If you don't want to buy one see if you can borrow a good working one.
But there are obviously other things that can cause your problem.

Crank Position sensor,
Cam Position Sensor,
Boost Leaks,
Bad Wiring Harness,
PTU,
Coil Pack
Plugs
Plug Wires
Injectors
Inject Resistor pack
Low fuel pressure

Basically anything that tells when to fire and anything that is apart of that.

I too have a random misfire but my car doesn't stutter or anything just throws a cel. It is very frustrating.