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Old 11-19-2013, 08:05 AM   #1
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RPM drop

After a cold start and letting the engine warm up until the RPMs settle, I noticed that occasionally my RPMs will drop to the point where the engine almost stalls on the FIRST time I hit the gas. If I let off it comes back, and then I don't have the problem anymore after that. It only ever happens on the first time I hit the gas. Does anyone know what would cause this or what I should do about it? Temperature outside doesn't seem to change the issue.
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Old 11-19-2013, 08:09 AM   #2
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After a cold start and letting the engine warm up until the RPMs settle, I noticed that occasionally my RPMs will drop to the point where the engine almost stalls on the FIRST time I hit the gas. If I let off it comes back, and then I don't have the problem anymore after that. It only ever happens on the first time I hit the gas. Does anyone know what would cause this or what I should do about it? Temperature outside doesn't seem to change the issue.
Hmmm only when your first start it up? I'd start with cleaning maf, iac, possibly TB, run some seafoam, see if that helps.
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Old 11-19-2013, 08:12 AM   #3
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After a cold start and letting the engine warm up until the RPMs settle, I noticed that occasionally my RPMs will drop to the point where the engine almost stalls on the FIRST time I hit the gas. If I let off it comes back, and then I don't have the problem anymore after that. It only ever happens on the first time I hit the gas. Does anyone know what would cause this or what I should do about it? Temperature outside doesn't seem to change the issue.
Are you tuned? I always allow my car to run until the rpms drop before I move but it never gets that low. When I first crank up it's around 1,200-1,300 and then it drops to around 900-1,000. That's when I roll out.

---------- Post added at 09:12 AM ---------- Previous post was at 09:12 AM ----------

If you are tuned it could be that your idle is set too low.
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Old 11-19-2013, 06:23 PM   #4
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Mine does the same thing!! Can't figure it out either! I'm curious what might be the cause as well.
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Old 11-20-2013, 07:31 AM   #5
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Are you tuned? I always allow my car to run until the rpms drop before I move but it never gets that low. When I first crank up it's around 1,200-1,300 and then it drops to around 900-1,000. That's when I roll out.

---------- Post added at 09:12 AM ---------- Previous post was at 09:12 AM ----------

If you are tuned it could be that your idle is set too low.
No tune, stock as stock can be pretty much. I do what you do, let the car warm up and the rpms will settle around 900 at idle. When I go to roll out they drop really low when I hit the gas. Obviously the first reaction is to let off and it comes back, and then it works perfectly fine after that.
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Old 11-20-2013, 10:45 AM   #6
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No tune, stock as stock can be pretty much. I do what you do, let the car warm up and the rpms will settle around 900 at idle. When I go to roll out they drop really low when I hit the gas. Obviously the first reaction is to let off and it comes back, and then it works perfectly fine after that.
I'm clueless but Ford will probably say it's "normal"
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Old 11-20-2013, 12:44 PM   #7
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I contacted my dealer yesterday asking about this issue. I was told, this is a normal issue with the 5.0L engine and it is nothing to worry about. I guess they contacted ford and that was the answer given. Hope this helps!
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Old 11-20-2013, 03:22 PM   #8
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I'm clueless but Ford will probably say it's "normal"
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I contacted my dealer yesterday asking about this issue. I was told, this is a normal issue with the 5.0L engine and it is nothing to worry about. I guess they contacted ford and that was the answer given. Hope this helps!
You correctly predicted Ford would say it was normal haha
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Old 11-20-2013, 09:57 PM   #9
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You correctly predicted Ford would say it was normal haha
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Old 11-21-2013, 12:21 AM   #10
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Tried the idle relearn? Usually have to do it if you disconnected the battery.
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Old 11-21-2013, 07:39 AM   #11
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Tried the idle relearn? Usually have to do it if you disconnected the battery.
Didn't disconnect the battery but probably wouldn't hurt to try anyway
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Old 11-21-2013, 04:25 PM   #12
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I have this same problem. I will be at a stop light and the idle will be normal and steady. Then all of a sudden is will drop to 500 sometimes even 400 rpms then spike to 1000rpms. I even get some stalling at times which is kind of annoying. I am VMP tuned with a jlt cai. I heard the JLT cai can have some stalling and surging issues. I'm going to log it and send it over to Justin. Im sure he can smooth it out. I read you are stock OP so thats weird. I didnt have this problem when i was completely stock.
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Old 11-21-2013, 05:08 PM   #13
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I think what is happening is that your fans are kicking on. Do you notice it happens more when in traffic, or idling at a long light? Its normal for the idle to drop for a second and bounce back up when the fans kick on.
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Old 11-21-2013, 05:40 PM   #14
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I think what is happening is that your fans are kicking on. Do you notice it happens more when in traffic, or idling at a long light? Its normal for the idle to drop for a second and bounce back up when the fans kick on.
Could be a leak in the tubing.
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Old 11-21-2013, 05:54 PM   #15
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Could be a leak in the tubing.
Not likely. A vacuum leak would cause a constant idling problem . The reason the RPM drops when the fans turn on is because of the extra draw of amps from the alternator.
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Old 11-21-2013, 07:16 PM   #16
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mine does it on a pretty consistent basis. If I'm in traffic and slowly moving in gear it runs fine. When I stop at a light they drop from idle and then shoot back up. Sometimes, when I go into neutral from gear the car with go to idle and sometimes stall. Its doesn't always stall but it does it on occasion. I think it has something to do with the jlt cai and the tune. Time to run some logs and so the tuner (justin at VMP) can fix this
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Old 11-21-2013, 07:43 PM   #17
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mine does it on a pretty consistent basis. If I'm in traffic and slowly moving in gear it runs fine. When I stop at a light they drop from idle and then shoot back up. Sometimes, when I go into neutral from gear the car with go to idle and sometimes stall. Its doesn't always stall but it does it on occasion. I think it has something to do with the jlt cai and the tune. Time to run some logs and so the tuner (justin at VMP) can fix this
I'd lean more towards the tune. Maybe increase the idle
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Old 11-21-2013, 08:25 PM   #18
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I'd lean more towards the tune. Maybe increase the idle
Agreed. However, when it decides to idle fine and not drop and be screwy its right at 600 - 650. I wouldn't mind having the idle risen to 700 - 800 rpms if that gets rid of the stalling. Its annoying at well as embarrassing being at a stop light and my car shuts off
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Old 11-21-2013, 10:11 PM   #19
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Agreed. However, when it decides to idle fine and not drop and be screwy its right at 600 - 650. I wouldn't mind having the idle risen to 700 - 800 rpms if that gets rid of the stalling. Its annoying at well as embarrassing being at a stop light and my car shuts off
If its stalling out, its definitely the tune. 600 rpms is a low idle. Mine idles at 750-800 rpms stock. Ill be loading my tune tomorrow and ill see where it idles after that.
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Old 11-21-2013, 10:31 PM   #20
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If its stalling out, its definitely the tune. 600 rpms is a low idle. Mine idles at 750-800 rpms stock. Ill be loading my tune tomorrow and ill see where it idles after that.
Yea I'm pretty sure mine idles at 1k
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