1993 Montero 3000 12 valve Intermittent RPM Drop
 

Hey fellow Montero Owners,

I have a 1993 Montero LS 12 valve 3000. I live in Costa Rica and we have tough conditions for cars here. So I have been having issues with my motor after running for about 1.5 hours at highway speeds. I am getting intermittent power loss from the motor and will drop RPMs then surge back up. And when climbing hills power is severely reduced and surging RPM. I will begin "feathering" the pedal to minimize the surging but it will continue until I stop the vehicle and let it sit for 30 or so minutes. I was getting a MAF sensor code from what I could tell. So I replaced MAF and problem still persists. Motor will run fine full power for a solid hour in 89F degrees weather, which is our typical air temp. But by about 1.5 hours of continuous running the motor will start showing the same symptoms and begin loosing power and intermittently drop RPM's.

I am not sure where to begin. Recently cleaned injectors, plugs, throttle body, replaced MAF. Car is not overheating, but something makes me feel like the heat of continuous operation is affecting fuel/intake/air somehow.

Looking for any feedback on this issue. I have searched thoroughly but have not found much info on my current issue.

Same issue
 

Im having the same or similar issue, the rpms will drop suddenly for a second and sometimes climb back up as the car is rolling, other times the truck will turn off while driving and i would pull to the side of the road remove the key from the ignition and wait for a relay to click by the the passenger kick panel, after the relay clicks im able to start the truck again only for it to turn off again at any given time really, the wierd thing is that this is the second Montero I have had with this issue.