Houston Kid

Since I got zero replies in the engine problem forum, maybe someone in here has an idea.

2011 5.0 4x4 with 133,xxx miles on the odometer. About a week ago the truck started to idle very low. Around 500 rpm. Idle is smooth just low rpm. Push the gas pedal and the truck surges a little then all is good. It's worse after the engine has warmed up. I am going to clean the MAF sensor to see if that fixes it. If not, any other ideas as to the cause?

Once moving the engine is fine. Zero issues with acceleration or anything else.

I bought MAF sensor cleaner and TB cleaner today. Should have time tomorrow to use them.

JakeEllis

I am having this SAME EXACT issue with my 2013 5.0 right now! It’s driving me crazy. My mileage is at 139,000. If you get it figured out let me know and I’ll do the same. Are you getting any codes? Only code I am getting is a P0230 which points to a fuel issue but I’ve pretty much done everything except change out the pump at this point. Good luck!

gDMJoe

After warm-up and/or a cold start with an ambient temperature (say of 70°F or more) the engine, coolant, etc. temperature would be the same or at least +_ a few degrees. MEANING: At start-up the engine doesn't need to perform the normal cold-start-up routine - higher RPM, enriched fuel mixture.

In those cases (warm-startup and higher ambient temperatures), 500RPMs is normal. *At least that has been/is my experiences - purchased *new*, 60,000+ miles.
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05 super

My 13 3.5 Eco did this..actual idle was 300 when warm in drive and foot on brake. Cleaned throttle body and even raised idle with my programmer. Nothing helped. Never did figure it out.

Houston Kid

In a couple of hours I’ll be cleaning the TB and MAF sensor. Maybe it will work.

It does it worse actually when warm. The surge part is worse. I have zero codes.

Its summer in Houston so it ain’t getting below 78-80 at night. So below 70 is not an issue.

Houston Kid

The initial drive around the block after warming up the truck seems to indicate the once dirty TB and now clean MAF sensor have solved the problem.

13XLTEco

Normal. Why does the warm/hot idle need to be faster than 500 rpm ?

Spiky

Holy crap!!! How did it get that dirty? Admittedly, I wasn't at 133k when I cleaned mine, but it had deposits on like 1/3 of the door.

13XLTEco

Using an oiled or 'high flow' filter ?

Houston Kid

I don’t know that it has to be. I do know the truck normally idled around 600-700 and never had an issue with a slight surging at slow speeds while parking and backing up or moving from a dead stop.
After the cleaning it’s idle is right at 600. Hard to say exactly but it’s just a hair over the 500 mark.
No more slight surging.