4.0L Engine power problem

[fes007]

I have a 96 4.0 Ranger manual tranny. For some reason It has the problem of idling low, no power and runs rich when it has this problem. This is an intermittent problem that occurs about every ten to fifteen minutes. I don't have much power until I step on the accelerator at wide open throttle. I can turn the engine off and then back on and the problem stops. This happens more often when the weather outside is cold, or really humid. I have changed the MAF, IAC and still I can't find the problem. It does not throw a code either. My friend is a Ford Mechanic and he is not sure what the problem is. I am stumped and really frustrated at this problem. Any advice? Thanks.

 

[Spitfire1975]

Have you checked/replaced O2 sensors? Fuel Pressure? TPS? Plugged exhaust? What is the compression/vacuum?

 

[fes007]

I haven't checked the o2 sensors. I have checked the fuel pressure and it was ok. The fuel filter was changed and so was the fuel pump. I am not too sure how to check the o2 sensors.

 

[Spitfire1975]

There is a voltage check you can do backprobing the wires, but you have to do it when the engine is hot. If you haven't changed them in a while you should just do it. If you have a slow or dead O2 sensor you run the risk of clogging your catalytic converters. Check the wiring/connectors on them closely as well. They sit next to a lot of heat.

 

[fes007]

So I changed the O2 sensors and now I get a CEL code P1152 indicating a rich condition. I also still have the same problem with loosing power and shuttering during the 10 minute intervals. My friend suggested that I change the coil pack since the problem is intermittent and I can cycle the key and get it to stop. I have a new coil pack and I am going to install it today. If anyone has any ideas what the problem is please feel free to add your input. Thanks.

 

[chazzone]

So you know that the O2 sensors were bad, now you need to check the coolant temp sensor.

You should also disconnect the battery for a few minutes to clear the memory.

 

[fes007]

How do we check the coolant temp sensor?

 

[Big Jim M]

They are really cheap.. I just swap in a new one if I am having problems.
Big JIm

 

[fes007]

I went and scanned my truck. The CEL code is P1152.
Here is the Freeze Frame Data:

Fuel System 1 -closed loop fault

Calculated load - 58.4%

Engine Coolant Temp - 203 degrees F

STFT Bank 1 - 4.6%
LTFT Bank 1 - 10.1%

STFT Bank 2 - 4.6%
LTFT Bank 2 - 0.0%

Engine RPM -1708 rpm
Vehicle Speed - 30mph

I am still really clueless why my truck will shutter and miss after each ten minute interval.

 

[dzk007]

Look for a vacuum leak in the vapor canister purge system. If the solinoid opens and pulls straight air it would do exactly what you are getting.

 

[fes007]

Would that relate to the problem I am having every ten minutes with the rough idle and lack of power or just the CEL Code P1152?