Hello All,
I recently added 1.6 roller rockers and a few weeks later aCorsa exhaust system. After the roller rockers were installed everything seemed good, but after the Corsa exhaust was installed I noticed a"hesitation" during WOT acceleration, from a stop, when shifting into 2nd gear (automatic). As this slight power loss occurs at redline, I can hear a loud "pop" coming from the exhaust too.The car never did this when it was stock. When I accelerate, and look at the RPM's, everything is smooth until the redline, and then, it feels as if the rev limiter is kicking in and / or the timing is being retarded because you can feel a slight power loss.

I don't drive like this every day, but it would be nice to figure out what has caused this and correct it. Any ideas?

CG.

 

I had one in my shop one time that was acting similar to your condition and it turned out to be the igniton coil. Not sure on yours other than making sure your valves are adjusted properly. [8D]

 

You need to have the car diagnosed by someone good (ASE Certified or similar) with the proper equipment to really check out ignition, fuel injectors, timing, air fuel mixture, etc. It could easily be the ignition coil as mech259 says, or it could be that the combination of the improved breathing from the rockers and the freer exhaust has just barely pushed the tuning over the limit so that close to the redline in 2nd the engine control module sees something it does not like or cannot control well.

Either way you need to get it looked after: ignition coild don't stay "only a little bad" for long, and if itis a tuning issue it could mean that you are both not getting all the power you could get with a good tune, and that you are possibly running too lean and thus damaging the engine if you get into the throttle a lot.