Toyota Repair: 98 Camry 6cyl auto runs very rough, toyota technician, secondary ignition

Question
A few times my Camry has started to run very rough after driving at high
speed on the highway. I notice it when I am driving at high speed then slow
down a bit. It runs very rough at idle, feeling like it will stall, but it doesn't,
and when accelerating again feels sluggish and rough. After stopping the car
for say 20 minutes then start again, it is fine and problem is not there. It
happens when the air-con is on but not sure if this is related. The temp is
fine. Normal slower speed driving  over shorter distances is fine. Only seems
to occur on longer, higher speed drives, but not always.
Thanks

Answer
Kate,
This could be many different issues. I don't know how many miles
are on the vehicle and when the last tune-up was. You did not mention
if the engine light is on. You need to take it to a Toyota technician
for an inspection. If I was there I could find the problem but we don't have that luxury. It could be a engine temperature sensor,
something in the primary or secondary ignition system or a dirty
intake or cracked or broken intake rubber hose. This is all guess
work from my end.

Tim