When I rev up the motor to 1000 rpm the engine sputters and theres a clunking noise. Its like the motor is about to stall out. This is only an issue after the motor has heated all the way up. It will do itevery time in reverse. Half the time in drive. And will even do it hit and miss in park. Idle is good. Driving above 1000 rpm is good. But if it holds at 1000 it'll start going crazy. I started out my hunt by cleaning the air filter and MAF and even the throttle body. The fuel filter us a year old. I havent checked for issues with the fuel pump but wouldnt think it to be so rpm specific. All spark plugs and COP's are new and tested good. I took it to mechanic and he said he was 95% sure it was vct solenoids. Just got my truck back and no change. I am lost. Please help me

 

Does the noise sounds like it's coming from the back of the engine? If so it could be the torque converter.

 

What about that fuel pump primer thing above the spare tire? As I understand, it will cause low RPM issues. Easy to check, fairly cheap to replace. Someone will chime in with the correct name... It escapes me at the moment.

 

The clunking sounds like it is coming from underneath somewhere but I can only do it with the window rolled down listening. It does it in neutral as well and from my understanding, which could be wrong, that the torque converter would be disengaged? And if not would that only be at low rpm?

 

And Stephen, no I have not checked whatever that is lol i never found anything about that in anything I looked for. I will look it up and see if the effects match what mine is doing

 

What you guys are thinking of is the "fuel pump driver module (FPDM)", and yes, it can cause similar symptoms.

 

Get ignition first class first . New boots etc /plugs done right . Hosp clean plug job with plugs torqued in 25 to 28 foot pounds . Many times people do a transmission job for misfires .
A clunk can mean a driveshaft universal worn . ,mine makes noise all the time when going into reverse .
VCT solenoids should be changed for new design , never a bad maint idea . Use OEM only . .
The fuel module that's been talked about is a big deal . They go bad sooner or later . Its the FPDM on the rear axle , Its the fuel demand module . This provides fuel pressure on demand ,there is no return line to fuel tank for excess fuel like the old system ,no fuel pressure regulator .But the module gets corroded and lets water in to circuit board . There is a sticky on this- read it/fix it .

 

Its not a single clunk its almost like if you had a metal ball in a metal can and shook it back and forth fast. Clunk clunk clunk and so on until the rpm pdrops back to idle when I let off the gas. But solenoids were changed but didnt stop the problem. Admittedly though, the engine sounds smoother after that change. But the mechanic checked the spark plugs and cop and they all checked out. No misfires.

 

wouldnt it cause this issue frequently and through different rpm though? I only assume beause it is part of the fuel delivery system

 

It is a future issue,discussed since it was brought up . . That noise is very disconcerting. I have been hoping my tranny holds for another 100k as I have serviced it . I will have it rebuilt and upgraded when it goes . Surely a local tranny shop can analyze your noise since its repeatable . Stay away from big chain types .

 

Check your exhaust system for loose catalytic convertor covers as well as for broken brackets and rubber hangers. Does your check engine light go "on" when you turn the key to run to verify it's working. Di your mechanic check for any engine codes? When was the last time spark plugs and boots were changed? While your under the truck check the fuel pump driver for corrosion as stated in previous replies. https://www.ford-trucks.com/forums/1...l#post11280092

 

I think the tranny is okay. Like I had said itdoes it in park neutral and also first gear and reverse. But at 1000 rpm in second gear orhigheritis just fine. And honestly if I just dont back into my driveway after work then I can back out in the mornings when the motor is cold and it doesn't do it. Only once the motor is heated back up.

 

Judging by the symptoms you describe; "engine sputtering, like it's going to stall out and making clunking noises" and "only when it's warmed up". It sounds like a classic case of VCT issues, to me. You probably have VCT solenoid issues, or an oil pressure problem causing the timing to go erratic. I am going to provide a link to a video with a truck that has bad variable cam timing symptoms along the lines you describe. Let us know if this is the same noise you're hearing.

 

This is the issue but I had the vct solenoids replaced. So I guess that means I have an oil pressure issue? It sounds almost exactly like that and only happens if revved up a little as he was doing

 

You could have a failing oil pump or a failed timing chain tensioner seal, reduciing oil pressure to the VCT and causing these noises. Another potential cause is a worn out crank thrust bearing. 2007-2008 F-150s occasionally had defective thrust bearings and would wear quickly to the point that would let the crank walk back and forth, causing a drop in oil pressure. If the thrust bearing ends up being the cause, unfortunately the only fix would be a rebuild or a new engine. I'm going to provide another link to a video from FordTechMakuloco on checking for bad thrust bearings.