I just purchased a 2011 c70 and supposedly the Turbo was replaced about 85k it has 90k on it and when I accelerate it wants to stumble or stutters between 2k and 3k and then smooths out past 3k it's worse under a load like driving up a steep hill. I replaced the plugs and it helped a little and so did running a bottle of fuel injection cleaner but it still stutters, my next thing I'm replacing is the coils, is this something common with the t5 motor. Any ideas to point me in the right direction would be greatly appreciated.

 

Have you inspected the intake / throttle body /MAF? You can try cleaning the MAF with a $6 can of CRC MAF cleaner (don't use carb cleaner as that may be too harsh for the MAF filaments) as well as the throttle body, check for any oily deposits which may be a sign of a failing oil separator (PCV system). Have you scanned for any fault codes? You also may have an intake air leak or a boost controller issue so I'd suggest getting some professional diagnostics done before you simply start swapping out parts. Also considering the coils go for $50 a pop and would not fail all at once, I'd be investing my $ and time in professional scan that checks the lamba under load, testing for air leaks etc.

 

I cleaned the maf with crc cleaner I've checked for vacuum leaks, I changed the spark plugs and will change the coils because not knowing how many miles are on the old ones it gives me a little peace knowing I know what and when they were changed, if it doesn't help putting in the coils I will go have it scanned . I value this car and want it operating at peak performance thank you for your response

 

If you are going to go and replace the coils anyways, you may want to do a compression test while you have the plug exposed. Have you owned the car long enough to know if its consuming oil? Also inspect the wiring harness that connects to the coils to look for any cracked connectors or corrosion on the contacts.

 

thank you I will do that when I swap the coils out. I plan to have it scanned to see if it has any codes and go from there.

 

sounds like a plan. post up when you find something.