The last 2 times I've come up from Tijuana to San Diego and had to go through the border traffic (splitting lanes, but still slow) my KLR struggles for power once I hit the freeway on the US side. It feels like it's running out of fuel. If I open the throttle and get going fast the issue passes.
The temperature rises almost to the top, but the fan comes on as it's supposed to. The oil is clean, and no smoking.
Also, the KLR gets a little jumpy at around 4800rpm in 3rd and 4th gear regardless of the temperature.
BTW, I didn't use Mexican gas, although I'm sure it'd be fine anyway.
18,500 mi, 2011 KLR, with thermo-bob 2.