2003 GU Patrol 3L Losing Power

[JackCollo]

There was plenty of fuel in the car every time it happened.

I replaced the air filter today and found that the old was really dirty,
I went for a 5 hr drive tonight and it is definitely still happening.

I was pulling a small trailer with nothing in it and it usually drove fine, but sometimes it decided that it wasn't going to go faster than 90 and the exhaust temp started to go up.
I didn't let it get over 400 degrees.

what temp did it go from and to. how quickly did it go up?
so the temp shot up when it lost power??
starting to sound like a dirty MAF duck down to supercheap grab a can of mass airflow sensor cleaner. pull the maff off and the pipe that goes from the top of the airbox that the maf is apart of and give a darn good spray down from as many angle.
cheers