[silverTL6]

Dealer claims they need to drive my ATS-V for an extended length of time (~40 miles) to diagnose a check engine light that was throwing misfire and under boost codes (now cleared and hasn't reappeared), along with shuddering on cold starts. Does that sound right? Seems a little odd / extreme for those specific issues, as I assume the same could be accomplished by letting the car idle or driving it semi-aggressively for a short length of time, if the goal is to warm up the engine before re-checking codes.

My concern is that the risk of something bad happening is far greater when the car is driven further from the dealership and for a longer period time (per the advisor, it may not even be the tech driving it). Perhaps they have insurance that would cover potential incidents, but it may be a gray area depending how far away it occurs, and the opportunity for someone to abuse it seems far greater as well given a longer timespan.

 

[TwinTurboFan]

There is no better diagnostic tool for these cars than HP Tuners. It will allow you to capture the problem in a data scan. Then we'll be able to see exactly which DTCs were triggered, and how dozens of parameters read at that time. Feel free to email it to me and I can assist with diagnosis at no charge. My direct email address is [email protected].

 

[silverTL6]

Thanks for the offer...sadly the car's already at the dealer and they've started the diagnostic (which is how they found the misfire and under boost codes), so I'm already on the hook to pay for that. Supposedly those codes were cleared and haven't re-appeared, so they're not sure why the car still shudders on cold starts.

Hence they're requesting the extended (~40 mile) drive to diagnose further, which I'm hoping to get some input on from others here as it seems unnecessary, but I don't want to object to it either if it's a critical step in diagnosing such issues.

 

[slicky]

They should just change the spark plugs if they have more than 30k miles on them and skip the diagnostics. I am assuming you paying for it and they will be screwing around with it for days "diagnosing" worn out spark plugs. Missfires under boost and rough idle is almost always caused by bad spark plugs, which this car likes to chew through pretty quick.

 

[silverTL6]

Just to update, it's been over a week since I got the car back after getting the codes cleared, and the car seems to be fine now. I had suggested they look at the spark plugs, not sure if they did but ultimately they weren't changed (luckily I wasn't charged for any of the diagnostics either). The theory is that something bad got into the fuel mixture, so they suggested putting in some fuel cleaner (which I did just in case), but it seemed fine even before that.

So chalking it up to temporary bad luck. They did also end up driving it up and down some hills for awhile to observe behavior...luckily the guy that drove it was an older and seemingly conservative driver (he was the dealership's shuttle driver and used to drive big rigs in his previous job), which put me more at ease. Thanks all!

 

[bleu18v]

Already done (apparently done right) but I was going to suggest you take their guy for a 40 mile drive.

 

[silverTL6]

^ Huh? He seemed like a cool enough dude, not the type that would go for a joy ride (or at least I hope my intuition about him is correct). Either way, the car is back to normal so don't have much reason to complain to the stealership 🤷‍♀️