2002 3.0 idling kind of roughly

[tattooedthomas117]

So I have a 02 2wd xlt extra cab ranger with the 3.0 and auto. I bought the truck with engine trouble kid told me his mechanic told him it had low compression in cylinder 3 and the kid couldn't afford to fix it so he sold it to me. So I built new heads head bolts water pump thermostat fan clutch and a 5.0 explorer radiator. When I pulled the head it turned out it burned and sunk 3 exhaust valves because the cats turned out to be garbage. So I gutted the cats and put the y pipe and rear section of cats on (all 5 catalytic converters are gutted) and the truck runs good off the top but it runs real rough at idle and just off the bottom then smooths out. Would this be due to all the cats being gutted

 

[renton]

Did you repair the valves? With no cats I guess you get a engine code? A way to check if it's causing problems is to unplug the primary O2 sensor and see if it idles better. I did this on a civic to discover my secondary O2 sensor was causing my idle problem. When you disconnect the main sensor it runs on a pre set fuel mixture.

 

[tattooedthomas117]

Yes I built fresh new heads with new valves with brand new head bolts whole new top end gasket set water pump and so on and so fourth. So Un plug the sensors just below the collectors by the manifolds

 

[renton]

Yes unplug the senors closest to the exhaust manifold, this will put the system in what is called Open Loop. Let me know what happens when you unplug it.

 

[tattooedthomas117]

The truck seemed to smooth out a little bit but it's still kind of rough

 

[renton]

In my experience this engine always idles a bit rough even when new. Only thing else I could suggest is to spray the throttle body with cleaner really good, that helped mine some.

 

[tattooedthomas117]

Right on thank you buddy

 

[renton]

Good luck, I know stuff that like can drive you crazy trying to figure out.