Misfire, Bad valve

[Justin13]

Hi all,

My girlfriends 05 Aveo started misfiring a few days ago. CEL is blinking, code po300 random misfire. I changed the plugs, wires, and coil pack and its still misfiring. Took it to a shop, they said one of the valves in cylinder 3 is bad. Compression test for cyl3 came to 60lbs. quoted 700 for the job.

My question is, the car is just shy of 59,600 miles. This seems very early for a major engine component to be going bad. Is there a recall or extended warranty on the valves? Thanks

[avguy]

No recall or extended warranty. And, aside from timing belt failure, bad valves are not common on Aveos. There is a TSB on valves, but it doesn't sound like what's happening with hers.
TSB #050601030 NHTSA ID #10017820

Did they also do a leak down test in order to determine it's a bad valve? If not, I'd take it to another shop (but don't say anything about the first diagnosis). The P0300 is a bit puzzling too, because I would have expected that the ECM can determine the delay is always coming from #3 and should set a P0303. All things(especially the repair cost) considered, IMO you should take it to another shop for a second diagnosis. And request a leak down test be done, if they don't do it on their own.