Idles rough

Tiny
DEREK97116
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I changed the plugs in my truck and I went to napa and they gave me ones that came up for my engine compared them and they have double the length threads than the ones I pulled out took the ones I pulled out to napa and he said that's a 1990s plug that's not for your engine I said well give me these that's what I pulled out and the ones I pulled out were gaped at 0.38 and on my hood it says the gap should be 0.65 so I compared the new ones on gap and same 0.38 so I threw them in and no change still a rough idle I took it threw emissions and It passed so what's your opinion on that
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Monday, January 6th, 2020 AT 10:14 AM (Merged)
Tiny
DRCRANKNWRENCH
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So you put in the longer thread spark plugs gapped at.38. You really took a chance on the longer threaded spark plugs. They could have hit the pistons. Also, the difference btween the.38 gap and the.65 gap is very large. It can make a big difference in performance. You should gap the new plugs to.65 and go to another parts store to see how long the spark plugs are that they give you.

As far as the idle, I still think it is a behaviour common to the Ranger. I read about it in a few forums. Probably something you can stop chasing.
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Monday, January 6th, 2020 AT 10:14 AM (Merged)
Tiny
DEREK97116
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No napa gave me long threaded ones and the ones I pulled out were short threaded so I went back and got the short threaded ones. And the ones I took out were gaped at 0.38 and the truck says 0.65 so I stayed with the gap that was already in there so that's why I am asking and I was also wondering about the set idle screw where is it and should I adjust it
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Monday, January 6th, 2020 AT 10:14 AM (Merged)
Tiny
DRCRANKNWRENCH
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Really good move getting the shoeter threaded plugs. You would think NAPA would have it together. What if you had used them and damaged your pistons?
As far as the gap, always follow the specifications for anything that are on the sticker under the hood.

The idle speed is contolled by the Power Train Control Module, PCM< and is not adjustable. Since the idle may be an issue, check for vacuum leaks and incorrect igniton timing. Also make sure the throttle body, EGR and PCV system are clean.
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Monday, January 6th, 2020 AT 10:14 AM (Merged)
Tiny
DEREK97116
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I cleaned the throttle body already and changed the pcv valve how do you clean the egr and my truck passed deq today here in oregon so there are no vacum leaks or it wouldent of passed
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Monday, January 6th, 2020 AT 10:14 AM (Merged)
Tiny
DRCRANKNWRENCH
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First inspect the diaphragms for damage and/or detrioration.
When you clean it use BrakeKleen, brake cleaner. When you spray out the passages, spray in the opposite direction of the flow. Meaning if a port is flowing into the intake manifold, spray it so that the entrance at the intake manifold is where you spray into. Unless, this will spray cleaner and contaminants into the valve and trap them.
Be easy on it, don't take a brush to it and mostly look fir damage or any loose connections.
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Monday, January 6th, 2020 AT 10:14 AM (Merged)

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