largecar91

I have a 2007 F-150 screw w/ 5.4. I have 130,000+ on engine. It has ticked forever. Recently it started something new. When I back up a small grade or even pull forward using anything but idle(no gas at all) the engine starts making all kinds of noises. Almost like the idle is so low that the engine is just about to shut off. If I put it in park or neutral and rev it up, it clears up. If I drive (non towing) and come to stop sign or light the truck does not do this. It idles fine. Always when towing and backing up it does it. Engine also has a dead spot when accelerating(mid range). If you back off throttle it picks itself back up. No codes are present. I have always used full synthetic oil. I replaced twice new one pc plugs(6 of 8 snapped removing 2 pc plugs). Still running original cam phazers. Bought truck new and really like it but engine sucks.

jkurtz04

clean the throttle body and go from there

UAHogsF150

Yes, start by cleaning the throttle body and MAF sensor. Did you replace any coils when you did plugs? Also, check your VCT solenoids. Are you throwing any CEL's?

largecar91

I get no CEL. I did replace coils. It really does not have a miss. At a normal idle it is smooth (except for the ticking). I will try cleaning the throttle body and MAS. I have run Sea Foam thru the gas and oil several times over the years but I never put it right in the throttle body.

Especial86

iTrader: (1)

After you clean the throttle body which is notorious for gumming up, check the FDPM in the back of the truck by the spare tire. These little boxes are known to rot out and cause all sorts of intermittent drive ability issues. Do a search for throttle body and FDPM.

largecar91

I have already replaced the fuel pump driver module about 8 months ago. I did use Sea Foam and ran it thru the vacuum system this weekend. I did get some smoke but not a lot. It did help the acceleration slightly but I still have the bad "dieseling" when the motor is hot and just above idle. Also I did unplug the VCT solenoid on Pass. side and it made no change in the engine sound or idle what so ever. i cant get to the driver side to unplug it cause there is a bracket in the way.

largecar91

Update. I had my shop pull bed and check out Fuel pump and sender(gauge has not been working). After replacing pump and sender they found a broken wire on sending unit and that was the problem. They also replaced all the coils and plugs again. Truck ran a little better but still did the dieseling at low rpms. I ride my bike most of the time until snow flies so I didnt put a lot of miles on the truck. Start driving truck again when weather gets bad and one day it dies on me. I replace the FPDM again. Runs great, no dieseling. This is for about 6 weeks. Then sometimes it wont start. Just cranks (not getting fuel) then it will finally start and runs fine but back to dieseling again. Truck had original battery so I replaced it and it. Still the same problem. Died on me last night. Cranked over great but no fuel(tank is full). Shoot ether in it and fires and dies. My buddy comes to tow me home and truck fires right up and I drive it home. I am seriously looking into dynamite as a solution. Help! Could it be the FPDM even though it is only 6 weeks old(its a Doorman). Maybe ECM??

largecar91

More updates. Truck wont start most of the time. replaced FPDM again(that's 2 this year). Yesterday it did start so i pulled it in and replaced the fuel pump. The truck started up and ran fine( I was afraid to go very far). Thought I had it fixed. Went home at lunch today to get my truck and it wont start again, It just cranks over I know it is not the FPDM or fuel pump. Sometimes it starts and sometimes it dont.

FordSilly

fuel filter?

wolfy53

I had a trans am that would randomly just not start. Finally my buddy the mechanic caught it doing it with his code reader. Turned out to be the crank shaft sensor. After that all was well.