2003 4.8 rough idle / misfire

[Languor]

On 2018-03-30 at 10:36 PM, sefiroxx said:

Same symptoms as an vacuum leak, runs lean and does idle search

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Just picked up a new one. $50 cad.  

 

Something else i noticed is you can you can hear what I think is spark noise randomly.  I heard it on both banks I think.  But can’t pin point what cylinder exactly.  

 

It had new new wires and plugs few months ago to try to fix this.   

 

But it I don’t want to go get coils if it’s not them.   And I’d prob get used ones that are confined to work tho

[Colossus]

how old are the original coils

 

[Languor]

12 minutes ago, Colossus said:

how old are the original coils

 

That I’m not sure.  Bought truck few months ago , I know I’m still not getting right fuel mileage.   

 

After er I changed the intake gasket it does seem to be more throttle response.   

 

But it you can still feel a little rough idle.  And the dome lights slightly dim with it too.  

 

Your thinking ing I should test to see if coils , are weak ?    No way really without a timing light ? 

 

Edit: actually you can hear what sounds like a spark noise sometimes , I put new wires and plugs in it recently. 

[Languor]

I keep reading about crank re learns?  Is this something that needs to be done time to time. / would it hurt to get one done / is it capabale with the torque pro app?

 

there ngk wires I had bought new for the truck.  I think I’m going to try get set ngk or ac delco plats plugs for it.   Sense I had thrown the new cheap ac plugs in I noticed it hesitation on dead stop.  We also tried to adjust the gap on the plugs.  

[Languor]

What has got me wondering after thinking.  When I got the truck there was a wire in the box in the protective covering.   Wondering if there’s a ground or something that got ripped out.   I tried different fuel pumps same results.   The fuel pump whine goes with the dim of the dome lights and such too at times.  

 

 

[Languor]

Went out and messed with the truck again today.  Looked at cylinders 3 and 4 as torque scan was showing them misfire count most around 400.  I found two plugs had the top part cracked where the wire goes on.  Imagine that was some of it.   They were the cheapest ac delco plugs I could buy.   Possibly explain why I hear a spark noise now and then.  

 

Mean any time I thrown the older ac plat plugs I took out of it in the place.  Misfire count is now down to 0 on them cylinders. 

 

Have feeling ing I’ll be checking the other plugs, but for today I only checked four of them. And yet I think it runs a little better. 

 

Question though, if I had a misfire count of like 8 on cylinder 8.  Is this ok or is it always supposed to be 0.  

 

Thanks everyone one for their time btw.