So I have a 2006 f150 4.6 with about 280000 km on it. Sometimes when I'm sitting at a red light idling my rpm needle moves. Nothing drastic but it sounds like it wants to stall out but it hasn't yet and it doesn't do it all the time. I have used sea foam and a new air filter and I have put in mid grade the last couple fill ups. Does anyone have any ideas? No codes have been tripped.

 

Maintenance history? Plugs, coils, throttle body cleaning, MAF cleaning, fuel filter, FPDM?

 

My mechanic says it wouldn't be my fuel filter but some have said it might. He said that it could be a sensor but wouldn't that throw a code?

 

Maintenance history ?

 

Not sure I bought the truck just over a year ago and I haven't really done much. Just oil changes and I don't imagine much mauntance was done.

 

Would definitely check plugs and coils. I really do hope they were changed...

 

I should add its not all the time, maybe when its warmed up and the rpm dips under 500 and then jumps back up to regular 600/ 700 and if you listen to the engine it sounds like it wants to stall out. I would say maybe every 15- 20 seconds. It hasn't yet but is this cause for concern? Other than that issue it runs good.

 

I have the same problem, if you find something that makes a difference, I would love to know. I've tried alot of things to fix it, but haven't got it yet. There are still other things I can try. I am just taking a break from throwing money at it.

 

If all of the above has been done, another culprit could either be one or both VCT solenoids needing replaced. Could also be 02 sensors...maybe even a slight vacuum leak.

 

Would all the issues throw a code out? My father in law thinks it might be the O2 sensors. If there is no code is there a way to check?