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Dan, Technician
Category: Ford
Satisfied Customers: 23955
Experience:  Independent Shop Experience, 2 Year Automotive Diploma, & Access to Information Database
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F150: I have a 2007 f150 4.6l, very rough idle, seems like

Customer Question

I have a 2007 f150 4.6l, very rough idle, seems like misfires...had throttle body replaced looking at MAF now. Not sure what the problem could be. Cannot keep throwing $$, local mechanic has no real plan.
Submitted: 2 years ago.
Category: Ford
Expert:  Dan replied 2 years ago.
Hello, my name is ***** ***** I'm here to help get your problem solved. Is the check engine light on or does it ever come on?
Customer: replied 2 years ago.
I rIt was originally on when throttle body was replaced, that did not solve problem but light did not turn on after that. I was told MAF sensor was next step. I read online that if it was the MAF sensor I could disconnect it to see if it changed idle, if it did MAF was bad. Problem did not change, check engine light came on. Wrench light came on too, turned off when I plugged sensor back.
Expert:  Dan replied 2 years ago.
Do you know what original code was before throttle body was replaced? Did check engine light ever flash? Thanks.
Customer: replied 2 years ago.
I do not remember the code, just that my mechanic said it pointed to throttle body or MAF sensor. This was a few months ago. Not a daily driver so it's just been sitting til I was ready to try it again. I do know, originally before I took it to shop I bought new plugs to try to fix myself. If you are standing in front of the truck looking at motor...driver side, two plugs furthest from cab were covered in oil.
Expert:  Dan replied 2 years ago.
Have those plugs been replaced since? Plugs covered with oil would be caused by leaking spark plug seals which would come with valve cover gasket kit. Then the leaking oil could cause engine to run rough.
Customer: replied 2 years ago.
I purchased the gasket kit and was going to replace myself. Looked a little out of my league so I brought to shop where they tried smoke test? Said there was no leaks to be found.
Expert:  Dan replied 2 years ago.
A smoke test wouldn't find this type of leak. Have those 2 spark plugs that were covered in oil been replaced?
Customer: replied 2 years ago.
I don't think I replaced them, I just cleaned them off.
Expert:  Dan replied 2 years ago.
The most common causes of misfires on this engine is spark plugs and coils. I'd start by replacing spark plugs and if that doesn't help use a spark tester to see if each coil can jump a 25kv gap and replace whatever coil has weak spark. Let me know how it goes or if you have more questions, thanks.