449er

The mechanic had the car up on a lift to inspect the underside of the car, geez

robert miller

I agree with you here same thing happen to me on my car when I chg out the plug wires. The bad thing here is on the plug wires you REALLY have to make sure that they are really on the plug snapped on it really really good. If not you will get a PO300 code.

That may have not been the problem but call back that dealer and ask them to check this as a problem.. Robert

JDSC8VETTE

I find it very hard to believe an abused car would be spotless inside and out. Usually an abused car will have other signs of abuse.

Thatsok

JoesC5

You can never tell how a car has been treated. A local dealer sold a new C7 Z06 to a local buyer. Wasn't too long(a couple of months) when the car was in the shop with a defective transmission(Tremec TR6070). Dealer and GM determined that the car had been abused and refused to repair it under the new car warranty. They(GM) finally agree to replace the transmission but the car's warranty was then blocked.

Then the original owner sold the car shortly after that and then shortly afterwards the 2nd owner brought the car in to the original selling dealer to have some warranty work done. Of course the 2nd owner didn't know his "slightly used" C7 Z06, that looked brand new, had a blocked warranty due to it being abused by the original owner..

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pickleseimer

Many of the causes of a P0300 code have already been discussed here. Some of these are easy fixes. The fact though is that the car is detecting a misfire. Hopefully it really is something simple. A decent scan tool will help identify the issue, and the result of such is missing from this story. The code itself is not necessarily an indication the car has been abused, but it doesn't inspire confidence when you're about to plunk down that kind of money. Might be the battery, a plug wire, loose cable, bad fuel; or could also be a manifold leak, MAF sensor, injector, O2 sensor, bad lifter or valve, cat, compression issues etc.

The fact that it is just a pending code shouldn't be casually dismissed as perhaps being a minor issue. In the case of misfires, the car makes a note of how many consecutive ignition cycles it sees the misfire. It doesn't illuminate the CEL on the very first occurrence of a misfire, rather if the misfire occurs on several consecutive ignition cycles (ie is confirmed as not being a fluke) then the CEL will be lit. I can check my FSM at the shop but I seem to recall on some other vehicles it takes two or more consecutive ignition cycles with the fault before the CEL is lit.

In a fairy tale, now a service tech can come along and reset the codes which turns off the CEL and then the whole process starts over. One could imagine that just after the codes have been cleared, a prospect comes along and test drives the car (the first ignition cycle), notices a rough idle but no CEL. Hmmm.....the prospect wonders if this is really a problem or just his imagination - well, no CEL, no problem, right? Might not even have a CEL on the second test drive, but eventually....the CEL comes on. If the dealer still has it on his lot, it's again possible the tech would just clear the code/CEL again and carry on. If the car was purchased, the CEL then shows up pretty soon and the burden is now on the new owner to see it through, perhaps depending on that CPO warranty that the attorney discusses above.

BTW, if the car truly was inspected for CPO certification, the presence of a tune would have been detected and the car wouldn't qualify. Now you have to wonder, if the car was just rubber-stamped for CPO status as the attorney above says has happened, where does that leave the purchaser when the tune is eventually uncovered? Hmmmm.....

The OP's instincts may not have been far off. JMHO