Hi,

My 1997 xk8 is having some trouble from the extreme Miami heat. (I've done the tensioners already about two years ago). It drives perfect, buttery smooth until the temperature outside starts to reach the 90s, then it will start surging(especially in traffic is where its most noticed). It's not enough to set of the restricted performance, but it's there. Whats interesting is that is will stop if I get on the highway for about twenty minutes, it thinks its because of the extra cooling airflow. What could it be???

 

It could be an overheating transmission. Check the fluid level first. Surging is usually related to the torque converter clutch in these cars. A 1997 has a recirculating fuel system that usually keeps the fuel cool enough to prevent heat problems such as vapor lock.

 

It's not the transmision, it also hapens in idle(in park or neutral). Tranny is rebuilt, so its perfect.

Could it be a coil?? Or fuel??