Originally Posted by 1slow370

yeah the scan gauge 2 will work i don't know how accurate it is for the air/fuel ratio i have one it was kinda hit and miss, it's great for a lot of the other stuff it does though. the best thing for air fuel ratio is and always will be an innovative lc1 wide band or two. the plug check method is actually fairly good when your talking about spark plug life. and being how much of d bags they are at your dealer they could have pulled out a plastic bag from one of your intakes, and gone joyriding in your car thinking your just some rich prick who has it better than they do. I bought my z and for the last 2 years anytime i tell someone about it they don't believe i bought it and want to know how much my parents paid for it. I've seen guys at dealerships do the whole reprint the shop order, and lye to people, if you don't walk in there and bend the head tech over your car, prove he's F'n wrong and make the service adviser your friend you are gonna get screwed at most dealers now a days. Think about it most service advisors are just salesman, and they don't bat an eye at bending you over.

Also you would have to be running catastrophically lean to have a power down like that normally if you are lean you get knock first then it goes limp. and they wouldn't really be driving like they stole it if it was misfiring bad enough to go limp because it would have died on them too my guess is they might have removed an obstruction from your intake or fixed a hose that came lose, reset your ecu then gone joyriding and told you it was the plugs as that is probably the easiest thing to tell a car noob when this happens. if it runs like crap because of something stupid that is easily fixed but they want to ring money out of you they tell you it's the plugs because they figure you have to know what those are (which is why they didn't really care to tell you where they are really because they probably aren't bad) then charge you 4 times book to put in new ones thankfully you pulled your car from them.