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Discussion Starter #1
Hi there.

I'm back to the forum after a prolonged absence 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 OBD system. A couple weeks later, the light came on again. This time, I had my independent mechanic plug in the reader... 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 is under 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!
 

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I think I would try a couple bottles of injector cleaner first like Techtron (I've used this stuff for a lot of years with great success )unless you run some real bad gas or your car sits for long periods of time without a fuel stabilizer Sta Bil you should not be experiencing this type of problem . I'd drop in a bottle then fill up with fresh good grade gas run it out and repeat .What codes are you throwing ? If you don't have a code reader to clear the code just remove the negative battery cable ,let it sit for a couple of minutes reattach and the code should be cleared . Replacing injectors is not difficult do a You Tube search to get an idea it does not have to be model specific and remember to disconnect power to the battery before you start .
 

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First we need the code. Next....I disagree a bit with Sting Ya. I believe the Techron ruined my HPFP. Nothing is EVER going to touch your intake valves and in the DI motor, nothing is ever going to clog your injectors. Not at 1200psi. Don't let a dealer tell you they can clean your intake valves. You have to have them walnut blasted. Injectors can go bad. Someone here had 2 bad ones IMSMC and he showed the spray. Usually if you are having the same misfire code, from what I've learned here, it's usually a blown head. If it's (IMSMC) the number 1 cylinder as it runs the hottest.
 

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Discussion Starter #4
Thanks for the comments... The code has consistently been a misfire on cylinder 2. I neglected to mention that the dealer did a leak down compression test and everything was normal. I'll also note again that engine performance appears to be completely unaffected.

Interesting to hear about your experience, The_Ghost. I was about to try the injection cleaner option...
 

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I would swap coil packs and see if it continues complaining about cylinder #2
 

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$2500 for injectors? You're freaking kidding me, right?

I realize the GXP DI injectors are expensive, but they're also not insanely difficult to replace. I'd suggest shopping around.

Also, it's pretty easy to test an injector. Have they done that, or are they just randomly replacing parts in the hope that it'll fix the problem? The easiest thing to do here would be to swap the coil and injector from the errant cylinder to another cylinder, and see if the misfire code follows it. Also, check the wiring harness connectors for the coils and injectors and make sure there isn't a broken wire. (It happens, surprisingly frequently.)
 

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Discussion Starter #7
I've already swapped plugs and coils. The cylinder 2 misfire code persists.

Tell me about it!!! $2500... Good grief. The car's only worth $8500. They did not test the injector. How do you do that? They did do a leak down test and found that there were no compression issues. Next I'm gonna swap the injector out and see what happens. I'll also check the wiring.

Thanks for the help. :)
 

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There a few ways (Google it), ranging from listening with a stethoscope (or length of rubber hose, or a long metal rod pressed against the injector), to removing the injector and seeing if it's firing (ie, spraying gas when it's supposed to), and others. It really comes down to comparing the operation of the potentially-bad injector to a known-good injector. If you have the proper equipment, you could also bench test it with a waveform generator and an oscilloscope.

Either way, if you swap only the injector to another cylinder, and the misfire moves to the new cylinder, it's a pretty safe bet that the injector is bad. Same goes for coils, etc. One injector cost between $200 and $400, as far as I can tell, and shouldn't be that difficult to replace. Takes about 20 minutes on the LE5, but the LNF is a bit more involved since the injectors go into the top of the head rather than above the intake manifold.

Save yourself $2000 and move the injector to another cylinder, replace it if the misfire code follows it.
 

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Discussion Starter #9
I concur. Interestingly, my wrench is friends with a GM master tech who works on a lot of the local late model Corvette club cars. He recommended a round fuel system cleaner first. We're gonna try it. I'll report back with our findings.

Thanks!
 

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Discussion Starter #10
Update!

Hi gang!

UPDATE! It's been over a year now and I'm still having absolutely no performance issues of any kind, but the misfire code has persisted sporadically and I've gotten not only cylinder 2 codes, but more recently, also cylinder 1. Coincidentally (or not), beginning a year or so ago, the safety switch on the clutch that allows the starter to crank began to malfunction intermittently. First, every 20-30 cranks, then increasing in frequency over the past year until I was getting one or two cranks every 20 or so starts. Obviously, I took it in and had that switch replaced (under $50), which solved the starting issues. At my last visit, my wrench suggested that perhaps the misfire issue was related to the repeated unsuccessful crank attempts due to the faulty clutch switch... Sometimes the switch would allow a partial crank and then cut off the power to the starter.

Since my clutch switch replacement, the check engine light went off by itself and hasn't returned... Hmmmm. I reset the OBD and will let you know if anything new happens.

FYI, my Sly 2007 GXP has 55k on the clock and I'm the original owner.
 
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