My 05 C-TT starts to develop a 3k-3.2k rpm surging after installation of Fabspeed test pipes. Car does pull alot harder , but I noticed this surging/hesitation problem right after installing the test pipes.

Car currently has K&N drop in filter, RSS intake plenum, fabspeed test pipes, and GIAC computer.

Could this problem be a result of needing a retune, spark plugs or diverter valve?

Any info is appreciated.

 

sounds like what exactly happened to mine. Installed the bypass pipes, air intake and diverter and 3 days later 3 coils went

 

Come to think of it the surging/hesitation does feel like mis-firing, but it only starts around 3k rpm during heavy load, and goes away at about 3.3krpm or so, most noticeably during this interval.

When your coils went does the cluster emit a check engine light other than obvious lumpy idle. Any aftermarket coilpack upgrade available?

 

Did some research, some people also experience similar hesitation/surging at around the same rpm and they said it's normal because it's the vario cams switching lift on the cams..

Hm...any idea?

 

the check engine light only came on if you got on it and stayed on it while it was breakig up