[flaj]

I know that this subject has been beaten to death but I'm at my wits end.
It started out as a "random misfire" at 76000 miles. At that time I changed spark plugs with info I got from this site. The code went to a cylinder # 3 misfire so I went to the coil packs, swapping them out to try to eliminate the bad one. No luck there so I bought a new coil pack and swapped it out with each cylinder -- no change. Then I looked for a cracked inter-cooler -- none found. I then did a compression test and found that cylinder #1 was a little soft ( 100 lbs vs 145 for #2,3 & 4) remember that # 3 is the one with the misfire. Every time I erase the code the light will stay out for about 100 miles then come on and stay on while the car runs fine.
No stumble , no limp mode 16+ lbs of boost in no tune mode.
I finally gave in and took it to a dealer for a diagnostic. Electrical system fine -- fuel system fine. I feel confident with the young gear head working on the car at the dealership. He thinks the next thing we should do is a leak-down test.
This Solstice has the BSR tune which I can bring back to OEM spects anytime. Any new Ideas

 

[The_Ghost]

Someone else just went through this in the last 2 months on here. I don't know if any update to the solution was given. I want to say that it was high pressure fuel pump, but I'm not certain. I will do a search and see if I can find it....

 

[flaj]

Someone else just went through this in the last 2 months on here. I don't know if any update to the solution was given. I want to say that it was high pressure fuel pump, but I'm not certain. I will do a search and see if I can find it....

Thanks Ghost.
It seems that if it is the fuel pump all cylinders would be effected but who knows.
I'm using a product that I've had good luck with in the past ( Restore) to bring up the compression in cylinder #1 so I can eliminate that as a possible cause. Again, the car runs fine.

 

[Somnambulator]

I've read about clogged/bad injectors on the forums a few times. there was a lot of debate and a lot of disagreement about this but it could explain misfires

Sent from AutoGuide.com Free App

 

[GS Stage 1]

Since you have a low compression situation on the first cylinder:

Start with that, even though your misfire is occurring on a different cylinder. I have never been a believer in coincidence. And I have a feeling if you find the cause of your low compression there, that this will lead you to the cause of your misfire.

Possible causes of low compression:

1. Failed injector seal.
(I am listing this one first because we know that failing injector seals have caused a variety of issues, including misfires. Have you run an E85 tune in the past? We know the corn will cause seal failures. And this would be the easiest problem to fix.)

2. Bent or burnt Valve.
(Now you are into engine territory. However, if you were very lucky; this would only require the head to be removed.

3. Failed Piston Ring.
(Tear down of entire engine required.)

If it was not for your low compression on one cylinder, I would suggest you chase down the HPFP and/or HPFP Control Solenoid. (I had a bad connection at the HPFP Control Solenoid pigtail wiring harness. This resulted in intermittent fuel pressure failure which in turn was causing misfires.) More often than not, with our cars; misfires end up being some kind of fueling issue. And since you already chased down the Coil Packs, then fuel is about all that is left; assuming the real underlying issue is not your low compression in cylinder 1.

 

[flaj]

Since you have a low compression situation on the first cylinder:

Start with that, even though your misfire is occurring on a different cylinder. I have never been a believer in coincidence. And I have a feeling if you find the cause of your low compression there, that this will lead you to the cause of your misfire.

Possible causes of low compression:

1. Failed injector seal.
(I am listing this one first because we know that failing injector seals have caused a variety of issues, including misfires. Have you run an E85 tune in the past? We know the corn will cause seal failures. And this would be the easiest problem to fix.)





2. Bent or burnt Valve.
(Now you are into engine territory. However, if you were very lucky; this would only require the head to be removed.

3. Failed Piston Ring.
(Tear down of entire engine required.)

If it was not for your low compression on one cylinder, I would suggest you chase down the HPFP and/or HPFP Control Solenoid. (I had a bad connection at the HPFP Control Solenoid pigtail wiring harness. This resulted in intermittent fuel pressure failure which in turn was causing misfires.) More often than not, with our cars; misfires end up being some kind of fueling issue. And since you already chased down the Coil Packs, then fuel is about all that is left; assuming the real underlying issue is not your low compression in cylinder 1.

Thanks GS and I agree with everything you said. Before I start taring the engine down I'm going to eliminate two things -- the HPFP control solenoid and the fuel injectors.

 

[scoobyless]

Random thing to check would be the fuel injector harness at the front of the block on the drivers side. You'll see a bundle of wires, and I had two of them rubbing against the block and eventually wear through giving me misfires because the fuel injector circuit was arcing against the block..

 

[COOLTURBO]

I just got the random misfire code AND the code for all 4 cylinders. p0300 through p0304. My GXP has 14300 miles on her, I had the codes cleared and hope its bad gas.. I didn't notice any misfires and she is running fine.

weird huh

 

[flaj]

Random thing to check would be the fuel injector harness at the front of the block on the drivers side. You'll see a bundle of wires, and I had two of them rubbing against the block and eventually wear through giving me misfires because the fuel injector circuit was arcing against the block..

Hey scoobyless I owe you a debt of gratitude. After a year of chasing that damn misfire I finally checked that jammed harness and sure enough that was it. I slit a piece 1" rubber hose and wrapped it around the harness and "Viola" no more misfire.
I had tried everything and was about to tear down the engine and start replacing injectors and the fuel pump when I read your post. Once again the Solstice Forum comes through. :thumbs::thumbs::thumbs:

P.S.
I just noticed that you said the drivers side - mine was the one on the passenger side but none the less the same problem. Now I'm going out to check the drivers side. Thanks again.

 

[mcurrier]

Pretty sure bad gas is the problem after my three experiences.

Got my Sol back in Jan 2007.

Had an issue in April 2007 where a LOUD backfire and then car went limp. Pulled over, engine idling badly, shut it off. Waited a few minutes then tried to restart. Nothing. Had dealer come and tow it in. They found nothing.

Car ran fine until August 2007 on a trip to Clearwater, FL, when, again, car went limp and was idling badly. Took to a dealer down there, waited all day, NOTHING! WTH???!?!

Went to start car and run errands a few days ago (5/22/18), as I was driving, I noticed engine light was on. Car was running fine. When I got home I hooked up OBDII diagnostics reader. It said #3 cylinder/plug was misfiring. Didn't hear anything, feel anything, car was running normal. Two days later engine light went out.

I JUST NOW REALIZED...............

In EVERY instance I had put the mid-grade gas in my car that day or day before. These are the ONLY 3 times I have ever used the middle grade! That got me to thinking...

I use Premium 90% of the time, and regular the rest (when I can't get Premium). These three times I used the mid-grade, they were out of Premium and I figured "what the heck".

This got me to thinking that, at most gas stations, people either go for Regular or Premium 99% of the time. Therefore, the mid-grade probably sits in the tanks a LOT longer.

I don't know if it gets contaminated, has a lot of sediment, the gas breaks down...or what...who knows. I DON'T CARE! No more mid-grade for me. EVER!

I need to run out this tank of mid-grade and then fill it up with Premium and run a few tanks through. I did add some octane booster and fuel injector cleaner to this tank of mid-grade, so I have not noticed any perceptible issues this time around, other than the engine light and diagnostic code.

I am 99.9% sure this is what happened in my case, and it may be very similar with a lot of you. Just thought I'd share my findings.

 

[The_Ghost]

Mid-grade is merely a mix of premium and regular at the pump. They do not have seperate tanks for this. Filling stations have one tank for premium, one tank for regular...and tanks for other types of fuel.

Never add anything to your fuel. I have a sneaking suspicion that the Techron led to the demise of my HPFP. It wore the seals out prematurely.

 

[vfx kid]

Misfire Code

Hi there. I haven't been on the forum for a while and may have missed some of the juicy discussions about this topic, so forgive me if I'm beating a dead horse. I'd just like some advice. A couple years ago, the check engine light came on in my 2007 GXP (45k miles). My local dealer reported the code as a cylinder 2 misfire. They swapped plugs and reset the system. A couple weeks later, the light came on again. This time, I had my independent mechanic plug in the OBD2... Got the same code. I had him swap coils. A couple weeks later, same code. I went to another dealership (the owner actually raced Solstices) and his mechanics recommended a top engine solvent flush, suggesting that there was carbon buildup around the valve(s). I did it. All was well for about 200 miles and then the light came on again. Yesterday, I went back to the same dealership (which now has new ownership) and they recommended replacing all of the injectors! That's a $2500 service on a car worth $8500. I've never noticed any issues with performance during the life of the car, so I'd love to just put a piece of electrical tape over the warning light and ignore it... Unfortunately, in my state, you can't get an inspection tag with an active code coming up.

Is it possible and/or difficult to swap injectors. Any other words of wisdom?

Thanks!