Fluctuating RPM on cold start (video)

[Jmcswig]

Hello!

I recently had to replace the alternator on my 2005 4.0 v6 explorer (153k) due to charging issue. While doing so I also replaced the belt, tensioner and idler pulley. Battery and terminals are also new.
Now on cold starts the RPMs fluctuates quite a bit for 5 seconds or so and then levels out. This does not occur if the engine is warm.

Video:

Additionally the new alternator started making a ton of noise after 3 weeks of use. Just swapped it out under warranty less than a week ago and the current has been quiet so far.

Any advice on what to look into on this issue would be greatly appreciated!

 

[Rick]

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Code P0506 on 2005 Explorer (Help!)

2005 4-Door 4x4 Explorer 117,000 miles I am 56 years old and know little-to-nothing about vehicles and don't know what to do. Service Engine Light issue...the light came on 11/28/Monday then went out for 2 days after I put in a bottle of Lucas Oil Fuel Treatment. (Of course I don't know...

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[Jmcswig]

Similar issue in this thread:

Code P0506 on 2005 Explorer (Help!)

2005 4-Door 4x4 Explorer 117,000 miles I am 56 years old and know little-to-nothing about vehicles and don't know what to do. Service Engine Light issue...the light came on 11/28/Monday then went out for 2 days after I put in a bottle of Lucas Oil Fuel Treatment. (Of course I don't know...

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Thanks for the info!

I cleaned the throttle body last night.. it certainly needed it! as seen in the before and after pictures below.
Planning to clean the MAF as well today or tomorrow. Will send an update once it's all back together.
Thanks again.

 

[Jmcswig]

Clean throttle body appeared to resolve the issue! Started up great the last two cold mornings; no fluctuations.

Thanks again!