Hey guys I have a 05 crew cabf150. Its in great shape and has 80k on it. All new spark plugs. It has a rough idle when I come up to a stop light or have it stopped. Not 100% of time but a lot. The minute I give it a lil gas it goes away. Had mechanic check my hoses for lose connection and all seemed tight. Any ideas of what this might be?? Thanks for any input.

 

I have a 06 screw lariat with the 5.4 that does the same thing, just had new plugs and fuel filter put in it about 1000 miles ago and still did the same thing. Had the dealership run some diagnostics on it and the only thing that showed up was that the #3 cylinder was below baseline on the power balance chart. Dealership wanted to pull the valve cover inspect the valve train and possibly pull the head as well which would have been around 2000 or so. I'm not completely convinced that its a valve train issue. I've ran a couple of different injector cleaners/fuel treatments through it cause i think it may be a fuel system problem. The last few tanks i have ran through it that i added fuel system cleaner i used Chevron Fuel system cleaner synthetic blend. It's about 12 bucks for the bottle that treats 20 gallons. After running one tank through i could tell a difference in a smoother idle, when it did shutter/stumble just a little it was a lot less noticable that before and a lot of the time it doens't do it anymore. I know these motors are prone to have injector problems which i'm thinking about changing when i get some extra cash to do so. But anyway this stuff seemed to help mine out and maybe will do so with yours as well. There are two different bottles that Chevron has one just says injector cleaner and the other is the synthetic blend Fuel System cleaner which is the one that i used. Hope this help ya out some as it did for me.

 

That's funny you say that because I talked with my mechanic tonight and he told me to use that exact stuff so I am gonna try it. Thanks man.

 

Clean the MAF..and throttle body

 

i will try. thanks

 

I run two things in my 07 4.6L and it helps with rough idles. I run Sea Foam and the Lucas Fuel Treatment. I don't know how much it runs everywhere else but I can find it anywhere from $5.99 for the Lucas up to $9.99 for the Sea Foam.