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  #1  
Old 11-06-2018, 06:00 AM
Kurt - 06 Ranger Kurt - 06 Ranger is offline
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Default Bucking and misfire at light load

Hello all, I am new to the forum here...

I have had my 2006 Ranger pickup for almost three years now, it is at about 96,000 miles on the 2.3L with manual 5 speed.

Since I had the truck it would buck slightly when cruising at a particular speed on a flat area and little load on the motor. I replaced the spark plugs and wires but made little difference.

Last year it started using oil and developed a miss under load. I removed plugs and found no. 4 to be oil soaked and fouled. I removed the head and had a valve job done and put it back together. I followed the timing instructions to the tee and feel very confident that part is correct. The truck runs much better now with noticeably more power but the bucking at light load has increased, the engine runs great under any other conditions.

I how have codes P0300, P0301 and P0303. Not a very logical set of codes to me. I sprayed the entire intake area with starting fluid to no change in engine speed. I unplugged the IAC and it immediately stalled. I am thinking coil pack or most likely EGR valve. When I had it apart, the EGR was still clean, the fuel injectors were spotless and the PCV chamber below the intake manifold was very clean as well, no massive oil or soot deposits.

Any thoughts from you out there?

Thanks for your time!
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Kurt
Calhoun, Ga
2006 Ranger, 2.3L, 5 speed
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  #2  
Old 11-07-2018, 06:26 AM
tomw0 tomw0 is offline
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Default Re: Bucking and misfire at light load

A thought is take a look at the MAF. It senses airflow, based on temperature drop on a heated wire, and could be coated with 'stuff', which would show less air coming in than actual. Also take a look at the air and coolant temp sensors, sort of the same deal. If the air temp is mis-reported, the mass of the air coming in would be off by a bit, possibly leading to 'lean surge'.
tom
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Old 11-07-2018, 11:12 AM
Kurt - 06 Ranger Kurt - 06 Ranger is offline
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Default Re: Bucking and misfire at light load

I will have a look at those items, it will likely be the weekend.

Thank you!
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Calhoun, Ga
2006 Ranger, 2.3L, 5 speed
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Old 11-08-2018, 08:52 AM
dvrich dvrich is offline
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Default Re: Bucking and misfire at light load

Quote:
Originally Posted by Kurt - 06 Ranger View Post
I will have a look at those items, it will likely be the weekend.

Thank you!

It's a good idea to clean the MAF sensor yearly.
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  #5  
Old 11-13-2018, 08:04 PM
Kurt - 06 Ranger Kurt - 06 Ranger is offline
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Default Re: Bucking and misfire at light load

Well, I fixed it for the most part but I think there is a more serious problem.

I found a Ranger at a self service junk yard with identical drive train (2006) and removed the MAP, MAF sensors and the coil pack. I cleaned everything and swapped parts one at a time, nothing made any difference. Then I realized it works fine when cold, for about the first 3-5 minutes of driving. That made me think of oxygen sensors so I replaced them with new ones. It now runs much much better but not perfect.

The bad news is that I checked the oil to realize it used a half quart in less than 1000 miles since I repaired the cylinder head. I am concerned there are bad rings in one or two cylinders that cause the flutter. I will check the compression in a week or two, then decide what to do with it.

Thanks for your replies!
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Calhoun, Ga
2006 Ranger, 2.3L, 5 speed
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  #6  
Old 11-14-2018, 11:09 AM
tomw0 tomw0 is offline
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Default Re: Bucking and misfire at light load

Where's the self-service boneyard? I'm down the road about 30 miles near Canton, and looking for an 89-94 2.3 cylinder head(actually the cam & followers, so a bad head is fine).
Given it runs OK when cold, it might be having a problem when it shifts to 'closed loop'. When cold, it runs 'open loop', and uses 'stored' values for timing/injection/etc. Warmed up, O2's cooking, it uses them, the MAF, the MAP(if equipped) to diddle timing, fuel pressure, pulse length, and IAC (throttle/rpm).
I'd get a scan tool and look for temp, etc sensors that are a little off. Do run a compression test, but FoMoCo finds a quart of oil per 500 miles (maybe 1k??) acceptable, and will do nothing if you bring in a new vehicle that uses oil.
tom
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