Hi there first time poster. I just bought a 2011 GTI 155 limited with 72 hours. I didn’t do a water test but the seller started it up and let it run for a few minutes while on the water hose. It sounded great! Smooth idle…reved good. Seemed good! It was stored under a shed. He said he hadn’t ridden it in 6 years but started it up about 3 years ago. He installed a new Die Hard battery with 260 cold cranking amps. Although it doesn’t fit In the tray very well. So fast foreword a month and I’m finally able to take it out for a test ride. Started right up. Backed off the trailer. Putted around for a sec to let it warm up a little. Hit the throttle and it took off good and hard. Set me back in the seat real good! About 20 seconds into it full throttle and it started sputtering! Sudden loss of power and would only get to 35mph. I could tell it was missing somehow. It almost felt like a dirty fuel filter or injector or something like that. It would actually kick back in and rev out like it should for a very quick second. Kind of reminded me of a two stroke going in and out of the power band. Then back to sputtering and no power. I took it back to the ramp and put it back on the trailer. Couldn’t figure out what the problem is. Nothing in the intake grate. Took it home and put new plugs in it. When I fired it up it started reving really high. Like 3500 rpms and wouldnt drop. Tried unhooking the battery to possibly reset the computer but that didn’t fix it. Did the same thing revving really high! I tried blipping the throttle to get it to come down but that didn’t work either. I eventually got the code for high exhaust temp so I quit trying after that. Can anyone help me figure this out? I put the battery on charge tonight to see if maybe it was undercharged causing weird issues.