Starts to buck at around 3 or 4k RPMs

chippyflava

Hopefully someone can help me on this. I have a '11 Touring Sports Package Manual Transmission. 5k mileage. I have installed AEM ETI cold air intakes and a Stillen catback exhaust. It has ran perfect since I got it a couple months ago with these upgrades. The other day it started downpouring and the roads had standing water. I'm positive I got a couple of waves through my grill and splashed on my filters. It started bucking and I couldn't drive faster than 65 miles an hour.

Pulled over and waited till it stopped and started back home. The problem was the same all the way home. I let the car sit over night and half the next day. When I started driving it, it was all messed up, but as I continued it performed better and better and finally the best it's ever run as far as torque and response.

A few days later I noticed that if I slowly accelerated it started to "buck" when I reached 3 or 4k RPMs. Now, if I accelerated fast it didn't do it, only rarely. So, I filled up and ran through some Octane Boost through the fuel thinking maybe I have a moisture problem and also cleaned the MAF sensors. Nothing is working. I also reset the ECU by unplugging the battery and still no fix.

Could this possibly still be moisture in the cylinders or plugs? I wouldn't think so after a week but, I have no idea. Could the exhaust have anything to do with it? Anyway, sorry for the ramble but I wanted to give all the details. If someone has a suggestion, I'd love to hear it.

Thanks.