Rough Idle with A/C on.....
09-25-2010, 04:58 PM
#1
Junior Member
Thread Starter
Join Date: Sep 2010
Posts: 8
Likes: 0
Received 0 Likes
on
0 Posts
Rough Idle with A/C on.....
I have a 2007 F150 Crew w/ 5.4......When the air conditioning is running it has a rough idle.....Also rough on acceleration until over 1000 rpm with a/c on. You can feel the rough idle in the truck.....Doesn't do it when a/c is off......Only had this truck for a couple weeks......Any ideas what the cause is or what to check?
07-15-2011, 07:00 AM
#3
Mark
iTrader: (1)
Miles on the trucks ?? could be getting close to tune up time..
07-15-2011, 11:44 AM
#4
Moderator (Ret.)
Remove the Throttle body and clean the carbon off of the back butterfly valve. This can effect the idle. Use cleaner specified for throttle body's; do not use carb cleaners, as the throttle body valves have a coating on them that can easily be removed with the harsher carb type cleaners. About a 45 minute job.
08-03-2011, 06:28 AM
#6
Junior Member
Join Date: Dec 2008
Posts: 10
Likes: 0
Received 0 Likes
on
0 Posts
Very similar problem for me too. Mine is a 2008 4.6L Crew Cab, purchased new in Dec 2008, that has only 17,000 miles, 9000 of which were during two road trips. It has had the rough idle when the AC is on essentially since new. The dealer puts me off (naturally) with the excuse everybody hears, "they all do it." If they do do it, they shouldn't all do it. Upon the slightest acceleration the roughness disappears and all is fine. What I have noticed is that the engine itself is not really idling rough. it looks to me like the drag of the compressor is causing the belt tensioner to shake back and forth a very great amount, sometimes nearly violently. That's where the feeling comes from inside the truck and through the steering wheel the entire truck is vibrating. Very annoying. The second the AC is off, the belt tensioner stops moving and all is well. Anyone else like this? How do I convince the dealer they all don't do it, at least like this? When my V6 Accord is running, you can't even tell the engine is on unless you look at the tach. Not so with this truck. Other than that,(and its gas mileage), this truck is wonderful.
08-03-2011, 06:54 AM
#7
Moderator (Ret.)
Ask the service manager for the Ford regional service managers phone number (ask politely). Then explain to this person what you have posted here. They "all don't do it", as this can be considered a saftey hazzard (almost stalling in traffic). You may be told to take it to a different dealership, but it should be covered under warranty even if the time has run out for you.
Trending Topics
08-27-2011, 09:46 PM
#8
Junior Member
Join Date: Dec 2008
Posts: 10
Likes: 0
Received 0 Likes
on
0 Posts
Rough Idle With AC on
An interesting development for my 2008 Crew Cab 4.6 from my 8-3-2011 post. The truck went to the dealer last Wednesday (this is now Saturday night). This time they were more than helpful. At first they thought the only thing wrong was the belt tensioner was defective and they would replace it. Then the next day I got a call and was told they had decided the cause of the rough idle feel and the belt tensioner moving back and forth so much was the air conditioning compressor was defective, not turning smoothly with a drag on its rotation so that every time it turned the drag would grab the belt and give the tensioner a jerk. The AC otherwise worked perfectly. The dealer has a new compressor and receiver/dryer on order from Ford's warehouse that's supposed to arrive on Monday to be installed on Tuesday and pick it up later that day. All covered under warranty. I hope this solves the problem? I bet they do too? Don't you think it wouldn't be so hard to come up with an AC compressor sooner than waiting from Thursday through Tuesday? On the other hand, if that works, and I get a new compressor, and it's free - better not complain any further. I'll let you know if the problem is solved. I had not heard of this sort of problem before - that is - a compressor that worked perfectly, made no noise whatsoever, but turned so roughly at idle that it caused the entire truck to shake and the belt tensioner to move so far left and right that it would sometimes reach its limits and hit the metal casing on each end of its travel.
