bushjc

This morning I had these issues start on my Vette - The car ran fine for a 50+ mile trip at speeds between 60-70. Backed into a parking spot and shut off engine then noticed I was too far over and restarted car. At that point she started chugging and misfiring - Still running, but very rough - Check Engine light began to flash and "Service Traction Control" appeared in DIC along with the Traction light (The vette rearend sliding?)

Turned off engine and restarted, no better. Came out 4 hours later and drove car to AutoZone to check code - P0300 - Random Misfire. They are saying plugs or ignition.

Drove the car back home and now beginning to search for cause/solution.

Any Ideas?

2008 Coupe A6

Any help would be greatly appreciated.

Russkier

Check the spark plug wires. It's common for them to fall out off the coils.

Lerxst

EXACTY what happen to my 427! Car was under-powered misfiring. Exhaust sounded weird. It was only a spark plug wire that came off. Threw the same error codes. Service Traction Control/ Service Active Handling System. All perfect now!
Check it you might be surprised.
S -

BSE1956

That happened to me too.
Scared the heck out of me.
Foolish design makes it easy for them to become undone.
Push the wire back up, and you'll be good to go!

FortMorganAl

"Service Traction Control" and traction control being disabled because of a loose plug wire?

Multiple unrelated issues sure sounds to me like low voltage causing computer confusion. Bad battery or bad alternator would be my first guess.

IrishSpuds

Nope - previous poster hit the nail on the head.

Due to inherent crap quality control this is the EXACT reason I experienced the same thing. LOOSE SPARK PLUG WIRES. Unfortunately common.

IrishSpuds

Happened to me on my 13 GS - you may be correct.

bushjc

Unplugged and reseated each plug wire back to its coil - restarted car - No effect - Guess I will be moving on to replacing plugs next.

IrishSpuds

Make sure you also check the coils and that none of the wires are burned from possible arcing. Examine the plugs before ordering new.

BSE1956

Mmmm. Sorry it was not the loose wire quick fix.
You don't say how many miles on your car, but a bad wire or coil could be an issue as well. Best to throw a code reader on it.
I have to say, mine spat out about 6 different codes on loose plug wire.
Damn confusing, even with the shop manual.
Good luck and post up your findings!

bushjc

Sorry for the oversight - 105k miles (yes, I know too many for a vette) - I am hoping that plugs may be the fix - She had 70k on it when I bought it and I have not changed them. Code reader at AutoZone returned P0300 - Random Misfire

v26278

Could be a clogged fuel injector.

FortMorganAl

That's going to give a lot more than a single P0300 code. Even P0300 shouldn't occur alone. You should also have P0301-P0308 to tell which cylinder is misfireing. And none of that has anything to do with traction control.

You need some more code reading. Service traction control is going to set codes and P0300 is not one of them.

wayback

Time to replace plugs anyway. I changed my wires at the same time.
Service traction control warning pops up randomly on these cars.

I would have the battery load tested and test the alt. Our cars are very sensitive to low voltage.

bushjc

I took the car to shop yesterday and had it put on their test computer -
Seems the misfire is coming from cylinder 1. The tech first moved the plug wire, issue did not move. Next the plug itself, issue did not move. Next the ignition coil - started car and it seems to completely solve the issue.

Turned off the car and restarted - misfire started again, same cylinder.

Then he connected a fuel test guage and tested. With the engine off, a steady stream of gas emerged. Started car and the stream became a powerful gusher.

I am taking the car back today to remove the Fuel injector to test/clean it.

Comments appreciated.

B-Vette

Let us know how it turned out in the end. I've never had this problem myself but I'm curious as to "why."

bushjc

Took the car back to the shop today.

The tech perform a test that he explained to me as a Fuel Injector cleaning test. He drew about a quart of gas from the fuel rail and mixed it with some type of cleaner. Then he removed the fuse from the fuel pump and he ran the car using the "mix" back through the fuel rail.

After running all the mix back through, he replaced the fuse and restarted the car. No effect.

He then hooked the car back up to the Diagnostics Computer and ran a pressure test on the injectors. He wanted me to post the reading and see if any of you might feel (as he does) that the fuel injector is bad.

Injectors 2 - 8 had a pressure reading of 15 psi and the number 1 injector was reading 20 psi.

Again, any assistance is appreciated!

BlueAngelSAE

My bet is on bad catalytic converters....dtc would lock in a p0301 if cyl 1 was detected as misfire.

bushjc

With all of the different testing that has been done, does this sound like a fuel injector issue? Is it normal for only one to go bad, or should I be getting ready to replace them all? I have only user top tier fuel, if that matters.

Or could it be something much more severe?

BlueAngelSAE

Could be injectors, but you typed almost exactly the correct procedures for injector cleaning...In the manual they mention the CATs and then I recalled riding around in a zr1 at Daytona that did the same thing.. At the NCM Sebring HPDE the corvette engineers said its a knock sensor, helping a friend I burnt my hands changing that darn thing out...didn't fix the issue..

After many tests they changed the CATs and the issue was resolved. Ask BEZ06 or go to ZR1 forum.

By the way, why didn't tech just move the injector to see if issue moved cylinders or why can't the tech tell you if it is in or out of performance tolerances...I know why and that is reason i bought the service manuals!!