RUNS ROUGH

[Dana Labbee]

Hey guys,
I'm sure one has an answer for me about my 2008 5.7 running rough. It seems that it happens going down road under very light throttle. It's not a slip. I had all the plugs replaced and a new fuel pump done at dealer and they said "It runs fine!"
To me it doesn't.

Help me, thanks.

 

[grizzstang]

Ever cleaned the throttle body?

Any codes?

 

[huntergreen]

Some have replaced the throttle position sensor for similar issues. Not sure if it triggered a code or not.

 

[Dana Labbee]

I will ck the throttle body, have not done that yet. Had a purge system fault after doing fuel pump. I erased it and hasn't come back.

Thanks guys.

 

[SyN]

I would make a special point to clean the TB every couple of years before an oil change.
I normally take them off to clean, but some are really hard to get to and remove so I just clean the best I can while installed on the motor.

Daughters 2012 Ford Edge had a very rough idle (Kind of a Surge). I admit I was lazy and hadn't cleaned the TB in 4 years.
Cleaned the TB while still installed on the car with the appropriate cleaner!
Took a few cranks to start afterwards!

The 3.5L finally started and began a very smooth idle once again.

This is where I would start my trouble shooting!
Just like Grizz stated above.

I will say: After I cleaned the TB - I went ahead and cleaned the air intake tube and MAF sensor and replaced the air filter. Then changed the oil! I guess you would call this --> A minor bit of preventive maintenance.

Edit: Just a thought--> Might think about it possibly being a weak coil pack?
Don't know: Just something to keep in the back of your mind.

 

[MidwestJ]

Amsoil Pi fuel injector cleaner. Or some other brand of PREMIUM fuel injector cleaner.

Can make a world of difference for fairly cheap.

 

[SyN]

Yes! Midwest that sure couldn't hurt one bit!
Maybe a double dose of PEA!

Amsoil / Red Line SI-1 / Gumout One-&-Done.

 

[MidwestJ]

Yes! Midwest that sure couldn't hurt one bit!
Maybe a double dose of PEA!

Amsoil / Red Line SI-1 / Gumout One-&-Done.

I like it