2010 precedent surging

[ncsupickle]

Hey Guys, new to the site here, but i have seen tons of good info. I have a 2010 Precedent I2 Excel with 1 year old PD Plus Batteries, stock motor, stock controller, 6" lift, 14" rims, and 23" tires. I purchased the cart from a friend less than a year ago that bought it in stock form, and performed the upgrades for me.

It ran 18-19 mph when i picked it up, but it now runs 15 avg. mph. I did deflate the tires to down to 10psi, which could cause some top end loss. As of late, it has been surging off and on throughout the throttle. Per GPS, i lose 1-2 MPH for 2-3 seconds, and then it seems to pick back up. It's beginning to occur more frequently, and i've began to start to troubleshoot.

I've been through the entire battery pack with a hydrometer (24 cells good) and a digital meter, and the digital readings are as follows: 8.66, 8.66, 8.67, 8.66, 8.61, 8.59. I've also began to research performance upgrades from D&D Motors, but I want to make sure the cart is in great shape now before i unload 4 figures on upgrades.

What's my next logical step?

Thanks in advance,

JD