2011 Yukon AFM issues
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CF Beginner
Joined: Feb 2020
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2011 Yukon AFM issues
Hi, I know it’s a Yukon but maybe someone can help me diagnose my problem.
Its my wife’s Yukon, 175,000miles 3rd owner we’ve had it for about 70,000 miles.
in the last few months it began over revving on downshifts making it hard to stop for stop. It will occasionally have a very hard shift into 5 or 6 gear. Then it started to occasionally stall at stoplights or signs. Lastly when driving at 35-40 on a flat road or downhill slightly the motor will turn 1100 RPM or so, all of a sudden RPMs drop to 500 and it’s like the cruuse control turns on and it holds 35 mph until a steep hill. I’ve figured out this is what happens before the over revving and stalling. Also figured out it’s in V4 mode when this all happens.
ive been reading up about the AFM system and lifter failures but I haven’t seen any symptoms like this.
Just replaced the throttle body, might have made it worse if anything.
any thoughts?
Its my wife’s Yukon, 175,000miles 3rd owner we’ve had it for about 70,000 miles.
in the last few months it began over revving on downshifts making it hard to stop for stop. It will occasionally have a very hard shift into 5 or 6 gear. Then it started to occasionally stall at stoplights or signs. Lastly when driving at 35-40 on a flat road or downhill slightly the motor will turn 1100 RPM or so, all of a sudden RPMs drop to 500 and it’s like the cruuse control turns on and it holds 35 mph until a steep hill. I’ve figured out this is what happens before the over revving and stalling. Also figured out it’s in V4 mode when this all happens.
ive been reading up about the AFM system and lifter failures but I haven’t seen any symptoms like this.
Just replaced the throttle body, might have made it worse if anything.
any thoughts?
CF Monarch
Joined: Oct 2017
Posts: 4,605
Likes: 269
From: USA
Hi, I know it’s a Yukon but maybe someone can help me diagnose my problem.
Its my wife’s Yukon, 175,000miles 3rd owner we’ve had it for about 70,000 miles.
in the last few months it began over revving on downshifts making it hard to stop for stop. It will occasionally have a very hard shift into 5 or 6 gear. Then it started to occasionally stall at stoplights or signs. Lastly when driving at 35-40 on a flat road or downhill slightly the motor will turn 1100 RPM or so, all of a sudden RPMs drop to 500 and it’s like the cruuse control turns on and it holds 35 mph until a steep hill. I’ve figured out this is what happens before the over revving and stalling. Also figured out it’s in V4 mode when this all happens.
ive been reading up about the AFM system and lifter failures but I haven’t seen any symptoms like this.
Just replaced the throttle body, might have made it worse if anything.
any thoughts?
Its my wife’s Yukon, 175,000miles 3rd owner we’ve had it for about 70,000 miles.
in the last few months it began over revving on downshifts making it hard to stop for stop. It will occasionally have a very hard shift into 5 or 6 gear. Then it started to occasionally stall at stoplights or signs. Lastly when driving at 35-40 on a flat road or downhill slightly the motor will turn 1100 RPM or so, all of a sudden RPMs drop to 500 and it’s like the cruuse control turns on and it holds 35 mph until a steep hill. I’ve figured out this is what happens before the over revving and stalling. Also figured out it’s in V4 mode when this all happens.
ive been reading up about the AFM system and lifter failures but I haven’t seen any symptoms like this.
Just replaced the throttle body, might have made it worse if anything.
any thoughts?
Last edited by oilcanhenry; Feb 14, 2020 at 11:16 PM.
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