2016 5.0 stutter at 1500-2000 rpm
5.0 DOHC V8 | 7.3 Gdzilla
Joined: Apr 2017
Posts: 3,987
Likes: 2,077
From: California and Utah
IMRC/intake manifold runner control.
There's an actuator (or two) at the rear of the manifold. The problem is not there, it is usually a broken linkage axle from the actuator to the internal manifold runner butterflies. These are not throttles per se, they are flaps that when closed cover a good portion of the manifold runner (cylinder runner), leaving a gap at the top of the runner cross section to create turbulent airflow at idle and off-idle so that the engine will run acceptably on lean idle fuel mixtures.
Once that plastic axle breaks, the butterflies are like a candle in the wind and will flop between closed and open and back again, creating the stumble you feel between 1500-2000 rpm... but the actuator is still working, and therefore no DTCs.
When it happened to my 2016 5.0 it was distinctly noticeable at 1700 revs. This was four years ago at least, and one of the best dealer techs could not find the source of the misfire, at first. Anyway, they replaced the entire manifold under warranty at the time with a supposedly improved part. So far so good but if it happens again, then it's out of pocket for me.
So, have your tech CHECK THE IMRC before you go throwing VCT solenoids at it or whatever other more expensive stuff. Cheers.
There's an actuator (or two) at the rear of the manifold. The problem is not there, it is usually a broken linkage axle from the actuator to the internal manifold runner butterflies. These are not throttles per se, they are flaps that when closed cover a good portion of the manifold runner (cylinder runner), leaving a gap at the top of the runner cross section to create turbulent airflow at idle and off-idle so that the engine will run acceptably on lean idle fuel mixtures.
Once that plastic axle breaks, the butterflies are like a candle in the wind and will flop between closed and open and back again, creating the stumble you feel between 1500-2000 rpm... but the actuator is still working, and therefore no DTCs.
When it happened to my 2016 5.0 it was distinctly noticeable at 1700 revs. This was four years ago at least, and one of the best dealer techs could not find the source of the misfire, at first. Anyway, they replaced the entire manifold under warranty at the time with a supposedly improved part. So far so good but if it happens again, then it's out of pocket for me.
So, have your tech CHECK THE IMRC before you go throwing VCT solenoids at it or whatever other more expensive stuff. Cheers.
Junior Member
Joined: Mar 2025
Posts: 24
Likes: 0
IMRC/intake manifold runner control.
There's an actuator (or two) at the rear of the manifold. The problem is not there, it is usually a broken linkage axle from the actuator to the internal manifold runner butterflies. These are not throttles per se, they are flaps that when closed cover a good portion of the manifold runner (cylinder runner), leaving a gap at the top of the runner cross section to create turbulent airflow at idle and off-idle so that the engine will run acceptably on lean idle fuel mixtures.
Once that plastic axle breaks, the butterflies are like a candle in the wind and will flop between closed and open and back again, creating the stumble you feel between 1500-2000 rpm... but the actuator is still working, and therefore no DTCs.
When it happened to my 2016 5.0 it was distinctly noticeable at 1700 revs. This was four years ago at least, and one of the best dealer techs could not find the source of the misfire, at first. Anyway, they replaced the entire manifold under warranty at the time with a supposedly improved part. So far so good but if it happens again, then it's out of pocket for me.
So, have your tech CHECK THE IMRC before you go throwing VCT solenoids at it or whatever other more expensive stuff. Cheers.
There's an actuator (or two) at the rear of the manifold. The problem is not there, it is usually a broken linkage axle from the actuator to the internal manifold runner butterflies. These are not throttles per se, they are flaps that when closed cover a good portion of the manifold runner (cylinder runner), leaving a gap at the top of the runner cross section to create turbulent airflow at idle and off-idle so that the engine will run acceptably on lean idle fuel mixtures.
Once that plastic axle breaks, the butterflies are like a candle in the wind and will flop between closed and open and back again, creating the stumble you feel between 1500-2000 rpm... but the actuator is still working, and therefore no DTCs.
When it happened to my 2016 5.0 it was distinctly noticeable at 1700 revs. This was four years ago at least, and one of the best dealer techs could not find the source of the misfire, at first. Anyway, they replaced the entire manifold under warranty at the time with a supposedly improved part. So far so good but if it happens again, then it's out of pocket for me.
So, have your tech CHECK THE IMRC before you go throwing VCT solenoids at it or whatever other more expensive stuff. Cheers.
5.0 DOHC V8 | 7.3 Gdzilla
Joined: Apr 2017
Posts: 3,987
Likes: 2,077
From: California and Utah
You'd have to look at the apparatus attached to the rear of the intake manifold, and look closely at all exposed linkage. No idea how you'd check inside other than through a visual inside the manifold. There are cameras on flexible probes for stuff like that but I do not own one.
As to your second question, I never experienced any vibration. What I experienced felt like it was a fuel and/or an ignition stumble during acceleration or constant throttle.
Junior Member
Joined: Mar 2025
Posts: 24
Likes: 0
You'd have to look at the apparatus attached to the rear of the intake manifold, and look closely at all exposed linkage. No idea how you'd check inside other than through a visual inside the manifold. There are cameras on flexible probes for stuff like that but I do not own one.
As to your second question, I never experienced any vibration. What I experienced felt like it was a fuel and/or an ignition stumble during acceleration or constant throttle.
As to your second question, I never experienced any vibration. What I experienced felt like it was a fuel and/or an ignition stumble during acceleration or constant throttle.
Junior Member
Joined: Apr 2025
Posts: 6
Likes: 3
Howdy folks.
I just bought a 2016 F150 crew cab 5.0, 2 wheel drive with 95,000 miles on it.
I've had it for about two months. During the first month the truck ran great. About a month ago I was driving it in the city and it acted like it wanted to die. Felt like it was running out of fuel. It was down to about a quarter of a tank and that was still the first tank of gas that the truck came with. RPM dropped off and truck started to stall. I pulled into a gas station and filled the tank and it never did that again.
At that point it kind of scared me so I started paying close attention to the truck. I noticed that at in-town cruising speeds (45-55 mph) it would hesitate a little. It was barely noticeable. Just felt like I'd hit a little bump. I don't know if it was just that I was paying more attention or if the problem got worse but I started noticing it all the time between 1500 and 2000 RPM regardless of gear. I'm able to manually downshift and get into that RPM range in any gear and it will do it pretty much constantly. It's worse right in the middle of that range, around 1700 or 1800 RPM. It idles beautifully and it accelerates with no problems and the stutter is completely gone if I'm above 2000 RPM.
I took it to a mechanic friend of mine and we cleaned the throttlebody and changed the spark plugs. He used his computer to reset the throttlebody after cleaning. I went home and put a can of seafoam in the gas tank and ran a can of seafoam through the throttlebody. None of that made any difference. Actually, it might've actually made it a little worse or I may just be noticing it more and more since I know exactly what to look for. I took it back to my friend who hooked it up to his computer and said everything looked perfect from a computer standpoint. It shows no codes whatsoever. The only unusual thing was low count random misfire on all cylinders and the VCT solenoids go out of range during that RPM range. I don't know a lot about them but the range seems to go up to 40 before it changes to red. If I'm holding the rpm in that range that it stutters then we can see that every hesitation is matched by that VCT solenoid passing that 40 mark. It's both of the intake solenoid's. Nothing out of range on the exhaust solenoids. He power braked the truck and ran the rpm up into that range and it would stutter while it was sitting still. It does not do it if you just run the RPM up there with the truck in park or neutral. We also changed the camshaft position sensor but no change.
I'm trying to decide whether to go ahead and change the VCT solenoid's or take it in to Ford and let them hook it up and pay them for the diagnostic.
Has anyone experienced this issue?
Thanks in advance, Jason
I just bought a 2016 F150 crew cab 5.0, 2 wheel drive with 95,000 miles on it.
I've had it for about two months. During the first month the truck ran great. About a month ago I was driving it in the city and it acted like it wanted to die. Felt like it was running out of fuel. It was down to about a quarter of a tank and that was still the first tank of gas that the truck came with. RPM dropped off and truck started to stall. I pulled into a gas station and filled the tank and it never did that again.
At that point it kind of scared me so I started paying close attention to the truck. I noticed that at in-town cruising speeds (45-55 mph) it would hesitate a little. It was barely noticeable. Just felt like I'd hit a little bump. I don't know if it was just that I was paying more attention or if the problem got worse but I started noticing it all the time between 1500 and 2000 RPM regardless of gear. I'm able to manually downshift and get into that RPM range in any gear and it will do it pretty much constantly. It's worse right in the middle of that range, around 1700 or 1800 RPM. It idles beautifully and it accelerates with no problems and the stutter is completely gone if I'm above 2000 RPM.
I took it to a mechanic friend of mine and we cleaned the throttlebody and changed the spark plugs. He used his computer to reset the throttlebody after cleaning. I went home and put a can of seafoam in the gas tank and ran a can of seafoam through the throttlebody. None of that made any difference. Actually, it might've actually made it a little worse or I may just be noticing it more and more since I know exactly what to look for. I took it back to my friend who hooked it up to his computer and said everything looked perfect from a computer standpoint. It shows no codes whatsoever. The only unusual thing was low count random misfire on all cylinders and the VCT solenoids go out of range during that RPM range. I don't know a lot about them but the range seems to go up to 40 before it changes to red. If I'm holding the rpm in that range that it stutters then we can see that every hesitation is matched by that VCT solenoid passing that 40 mark. It's both of the intake solenoid's. Nothing out of range on the exhaust solenoids. He power braked the truck and ran the rpm up into that range and it would stutter while it was sitting still. It does not do it if you just run the RPM up there with the truck in park or neutral. We also changed the camshaft position sensor but no change.
I'm trying to decide whether to go ahead and change the VCT solenoid's or take it in to Ford and let them hook it up and pay them for the diagnostic.
Has anyone experienced this issue?
Thanks in advance, Jason
What was eventually the problem?
