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Old 01-09-2020, 10:52 AM
PRTruckMan PRTruckMan is offline
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Default 04. 3.0 Cylinder 6 Misfire valve recession? Where to go from here?

I’ve got the dreaded PO 306 misfire in my 04 V6 ranger with the 3.0 engine. I think it’s gotta be the valve recession or th heads as it happens only at idle and wobbles for a minute before returning to normal just like the other people described, and it doesn’t do it if I hold the gas down and keep it above 1500 rpms or so. I’ve had spark plugs and wires and coil pack replaced by my mechanic and it didn’t help . I doubt it’s injectors or anything like that. I don’t really have the tools or time to tear this thing apart, how likely is it that it’s the valve recession?

I’ve been driving it for a few months and it happened after a month and in the month or two since it started misfiring it only got a little worse in that it happens a little quicker. If I ignore it what happens? How long do I have before I drop a valve? Will I still continue to wear out the heads and risk dropping a valve if I keep the rpms high and stop it from misfiring? What’s the best course of action here, it’s really not a bad truck besides this misfire issue. Someone saidthey replaced cam synchronizer and replaced the heads with some heavy duty ones and that seemed to fix the issue, but that was quite a few years back. Is there a consensus now on what to do with this misfire? Getting rid of the truck would be a real pain with the misfire so I’d either wanna drive it as is or get it fixed, or eventually just do an engine rebuild or put a new engine in it, or one from a ranger year without this problem. Any help would be much appreciated,

Thanks,
Peter
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Old 07-12-2020, 06:17 PM
SargeV6 SargeV6 is offline
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Default Re: 04. 3.0 Cylinder 6 Misfire valve recession? Where to go from here?

If you hear ticking coming from the passenger rear of the heads then most likely it's the start of the recession. I had the same problem with "Sarge"(2004 Ranger XLT 3.0 2WD 225,000 miles) which I'm in the middle of the rebuild right now. That ticking noise is the Rocker Arm which now has to much play between the rod and lifter causing it to tick because the valve is recessing. Also causing the cam syncronizer to miss because now the timing isn't accurate which will through codes. I picked up some new heads from Clearwater which all OEM problems are corrected and I'll tell you what they look strong and very well out together. $650 well spent I think. You can always do a compression test or a leak down test.

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Old 07-23-2020, 04:29 AM
PRTruckMan PRTruckMan is offline
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Default Re: 04. 3.0 Cylinder 6 Misfire valve recession? Where to go from here?

Quote:
Originally Posted by SargeV6 View Post
If you hear ticking coming from the passenger rear of the heads then most likely it's the start of the recession. I had the same problem with "Sarge"(2004 Ranger XLT 3.0 2WD 225,000 miles) which I'm in the middle of the rebuild right now. That ticking noise is the Rocker Arm which now has to much play between the rod and lifter causing it to tick because the valve is recessing. Also causing the cam syncronizer to miss because now the timing isn't accurate which will through codes. I picked up some new heads from Clearwater which all OEM problems are corrected and I'll tell you what they look strong and very well out together. $650 well spent I think. You can always do a compression test or a leak down test.

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How long or miles did you run it with the misfire? I’ve run mine for about 6k, maybe more. It’s gotten a little worse, but not really much at all. Still takes a few mins at a super long light when the truck has warmed up or drive thrus. Still clears out when I start driving. Can I keep it running it for a while? Will the motor eventually blow? It doesn’t really bother me that much, maybe if it starts misfiring consistently then I’d look into the heads. Any idea how much a shop might charge for labor to replace heads? Don’t think I’d be able to tackle it on my own.
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Old 07-23-2020, 05:28 AM
SargeV6 SargeV6 is offline
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Default Re: 04. 3.0 Cylinder 6 Misfire valve recession? Where to go from here?

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Originally Posted by PRTruckMan View Post
How long or miles did you run it with the misfire? I’ve run mine for about 6k, maybe more. It’s gotten a little worse, but not really much at all. Still takes a few mins at a super long light when the truck has warmed up or drive thrus. Still clears out when I start driving. Can I keep it running it for a while? Will the motor eventually blow? It doesn’t really bother me that much, maybe if it starts misfiring consistently then I’d look into the heads. Any idea how much a shop might charge for labor to replace heads? Don’t think I’d be able to tackle it on my own.
About 10k. Does it miss at all speeds? Mine only missed at highway speeds. In 4th-5th gear when I step on the accelerator. Cost- heads $650-$750 plus there's a $150 core. Labor is where it's going to cost ya. About $1500.00-$2000.00

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Old 07-23-2020, 06:01 AM
SargeV6 SargeV6 is offline
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Default Re: 04. 3.0 Cylinder 6 Misfire valve recession? Where to go from here?

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Originally Posted by SargeV6 View Post
About 10k. Does it miss at all speeds? Mine only missed at highway speeds. In 4th-5th gear when I step on the accelerator. Cost- heads $650-$750 plus there's a $150 core. Labor is where it's going to cost ya. About $1500.00-$2000.00

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Also I replaced water pump, cam syncronizer, all gaskets, head bolts(is a must), semi ported intake & exhaust manifolds, etc.

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