Miss or shutter on acceleration

[MEATLOAF]

01 4.0l SOHC 65k. My truch has developed a miss or shutter during mild acceleration, sometimes severe. Replaced fuel filter, fuel pump, DPFE sensor and TPS sensor. The odd thing is that it seems to run better at cooler outside temps. Could it be a bad MAF. No CEL, Thanks

 

[shane96ranger]

If I had to make a guess, I'd go with plugs and/or wires.

 

[RonD]

I had similar symptom on my '94 4.0
As engine warmed up it got worse, and over time it just got worse over all, but never quite as bad when engine was cold
Did fuel filter, air filter, Seafoam in tank for injectors, no harm but no help

Replaced plugs and wires............runs like new
Plugs were only a year old, so probably didn't need changing, but wires were original, so 18 years old, nothing lasts anymore, lol.

 

[freedom5]

You might also replace the "Engine Coolant" sensor. It's not the one that controls the temp guage. It's the two wire sensor that senses the actual engine temp and adjusts the mixture accordingly. It is also not an expensive item. I had a very rough running engine when it heated up. Replacing this sensor alleviated the problem.

 

[MEATLOAF]

Thanks, could you post a pic as to where it is located? I thought of that to but the temp gauge reads normal.

 

[adsm08]

What speed does it come in at? Somewhere near 45 MPH?

 

[MEATLOAF]

Speed various but mostly in that range (45 mph)

 

[adsm08]

Get the transmission flushed.

You are most likely experiencing torque converter shudder. It happens when the lockup clutch applies and releases or slips and catches quickly, and can usually be solved by a fluid flush. The reason you don't get it cold is because the converter clutch doesn't apply during warm up since most of the heat the trans makes is from fluid shear in the converter, which you don't get with the clutch applied.

 

[MEATLOAF]

adsm08 You just might be on to something. I have read about this but could never get any details. It does almost seem like trans shudder. I checked the fluid (synthetic) and it is still pink. Also the engine will not rev over 3k in park. I believe it used to. Does that mean anything? Thanks

 

[adsm08]

3K in park is the rev limiter, 100% normal.

It's not actually the fluid that causes TC shudder, it's deposits in the system. If you did a spill 'n fill to put the synthetic fluid in that wasn't good enough. It's not actually the fluid exchange that clears the dirt and fixes the problem, it is the flush solvent that gets run through before hand.

The 100% way to test if it is converter shudder is to hit the OD cancel when it starts doing it. OD cancel kills the converter clutch except for at low speed coast when you want it for engine braking.

 

[MEATLOAF]

Thanks, I'll check it out tomorrow on my way to work.

 

[FritzTKatt]

Adsm is likely correct, considering he knows his s*** very well. I had a similar shudder at all speeds (manual trans) and was replacing my wires when i found a disconnected vac line. Connected it, i think it was the fuel pressure regulator. Drives butter smooth now. Check for the stupid things like that. I've kicked myself a few times for having spent so much time on top of that motor and not noticing.

 

[MEATLOAF]

(QUOTE) The 100% way to test if it is converter shudder is to hit the OD cancel when it starts doing it. OD cancel kills the converter clutch except for at low speed coast when you want it for engine braking.

I tried this today and it didn't make any difference. I'm still open to suggestions. Thanks again.

 

[adsm08]

Next thing I'd try is getting a Ford scanner on it and watching the power balance. I've seen ignition coils cut out like that as they get weak. It will cause a one hit dead miss that acts a lot like TC shudder but doesn't throw a code.

If that is what is happening your mode 6 data should show it as well.

 

[MEATLOAF]

Where do I get a Ford scanner? Any recommendations? Thanks