2006 Z06 random misfire P0300
 

Got a weird problem that has been happening off and on for the last year or so. My car will randomly start to misfire on occasion. It will run fine. No problems. Then, chug chug chug chugchug chug chug. It will smell like gas, and a flashing engine light will come on with a P0300 code. Plug wires are fine, coils are fine, spark plugs are fine. This happens very seldomly and will go away after the car has been off for a half hour or hour. Sometimes it will misfire while idling. This only happens once every 3 months or so and goes away after I start my car up again (sometimes it has to sit for a few minutes).

I also got a code for a small evap leak recently as well (gas cap) but after replacing the gas cap, everything seems to be fine. What are your theories guys?

Dirty injectors?
Could it be a small evap leak other than the gas cap?
Vacuum line got nicked?
What about a bad vacuum solenoid?
Or bad 02 sensors? No codes for this though.
Bad 02 senor harness wire?
Maybe it is a bad coil/plug wire/spark plug? Could that cause a P0300?
Bad MAF sensor?

Thanks for the input.

Bump

Anyone?

Just have them check that when you take it in for the other warranty work on the heads.

#PIP3907: SES Light, Engine Misfire and Valvetrain Tick Noise - Inspect Valve Springs - keywords CEL crack DTC engine light MIL miss P0300 P0301 P0302 P0303 P0304 P0305 P0306 P0307 P0308 rattle rough valvetrain - (Sep 7, 2006)



On rare occasions, a SES Light, engine misfire, and valvetrain tick noise may be experienced. Upon inspection, a P0300 - P0308 DTC may be stored. This may be the result of a broken valve spring.

Valve springs have been checked but well see.

My first guess would be the MAF sensor.

Well it was found that I have a rough idle. Could that be MAF sensor related? Another dealership question... Lol

It would be a different code.

i have repaired two 08 zo6s that had this same issue. it turned out to be the connections under fuse box to injector fuses. terminals were not seated/clicked into locked position. also i would check all grounds. hope this helps.:thumbs:

I'll check today. Which fuses are they?

Any luck on this? I've got the same random problem. Although the car never seems to run bad, chug or anything. I just get a random P0300 that will clear and not come back for weeks sometimes.

where is this located exactly kind sir? thx

Bump

Louis, start to clean the MAF, Then do a cylinder leak test.
Injectors cleaned . After that, if probleme are still there.

Inspect valve spring. And after that, check for item shipped :crazy:

Hope this help

Seb

Check plug wires had one that was missing and tech at dealer could not find went out when it was cold checking plug wires #8 came off in my hand without hardly a tug. Put wire on end of problem the tech only hooked up the tech 2 tool showed misfire all over the place.
z51vett

I had the same thing just happen and through a process of elimination I think I have found the problem. Seems to be a bad coil pack. I replaced the plugs and wires and the car runs better at idle prior to a mis-fire. With the mis-fire being inconsistant i know it could not be valves or springs, so i moved to the coil pack. Code was P0307 so cylinder 7 misfire. I switched the coil packs on cylinder 7 and cylinder 3. cleared the old code started it up and no MIL. drove it around the block and it threw a code to my delight P0303 = Misfire on cylinder 3 I FOUND MY PROBLEM. TAKE THAT STEALERSHIP!!!!

Had a problem like that, turned out to be piece of crap over priced MSD coils. MSD even said they'd replace the coils but never did that was two years ago. every 2 months they would give me a story about manufacturing problems. I'll Never buy another MSD product.
Stock coils work great

ill remember that, thanks for the heads up

Thanks for all the replies guys it didn't notify me that anyone had replied. I recently replaced most of the whole drivetrain so this shouldn't be a problem anymore, shop did an awesome job on everything and I suspect it should be cured. Knock wood!!