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Oct 16, 2018 | 01:41 PM

Michael Reese

Thread Starter

Junior Member

Joined: Oct 2018

Posts: 1

Baffled

Hello friends. First time poster here. I’m a mechanic have been for years but I’m a little stumped. Friend has a 2001 Montero sport that very intermittently, like every couple months, seems to go into a limp home situation. Truck won’t go past 15 mph throttle wide open, no rpm increase, no stall, truck doesn’t die just won’t go. Problem always fixes itself before I get the truck and drives perfect. Has a p0421 no other codes so probably needs a cat but I’ve never seen this cause this odd drivability problem. Well maintained truck fresh tune up excellent condition 167k. Anybody had and solved this? Truck drives perfect for me and issue is very intermittent. Weather has no effect it’s just out of the blue truck loses all its power but doesn’t die or kick cel. Biggest problem is I can’t recreate it! Runs perfect with me so all tests show all good. Crazy just thought maybe someone knows something lol

Last edited by Michael Reese; Oct 16, 2018 at 01:48 PM.

Oct 18, 2018 | 12:22 AM

HunterD

Senior Member

Joined: Oct 2004

Posts: 2,044

From: Washington State

The P0421 will not cause that. Most likely its some transmission/transfer case sensor malfunctioning. It's too bad that you can't find a relationship of the malfunction to the weather or some other factor.
One idea is to check if there are any transmission related codes stored. It will not show up as "Check Engine" light, but as an intermittent flashing orange center differential light. You can "short" to ground a pin on the OBD connector and see what transfer case codes show up. I'm attaching a portion of the transfer case diagnostics section of the FSM for you. It describes how to get transfer codes out. There is also a section that describes various malfunctions that will cause limp mode/speed limitations. I hope you find this helpful in identifying the issue.

Attached Files