Engine Heisitation

[E.Denali]

I have a 1997 Ford Ranger XLT 4.0 L with 123,000 mi.

When I start my truck when it is cold and shift into first there is a two or three second hesitation during which the engine bogs down (and occasionally stalls), and hiccups before it gets power and runs. If I give it gas in neutral the engine revs fine, it is only when I put it in gear. After this initial 'hiccup/ hesitation' there is no hesitation while shifting and it runs fine. If I start it up again but the engine is still warm there is no hesitation/ hiccup either. It only seems to happen when the engine is cold.

I have cleaned off the MAF sensor, and have been running a cleaner through my gas tank to help with the fuel injectors, and I have recently replaced the fuel filter, but it just seems to be getting worse. Does anyone know if this could be an issue with the spark plugs (I don't think they have been replaced ever). If anyone has any ideas I would love to hear them. Thanks

 

[4.0L2WD]

seafoam

 

[Big Jim M]

The engine has a seperate temp sendor to tell the computer if the engine is cold or warm.
If that sendor tells the truth the computer allows for a cold engine... However if a lie is told and the computer THINKS the cold engine is already warm a similiar event such as yours happens.
So in short the first thing I'd do is to get a new computer temp sendor..
Big JIm

 

[E.Denali]

wouldn't that show up as a check engine light or as a sensor fault when you scanned the computer? I recently it scanned and nothing came back as far as a temp sensor.

 

[Big Jim M]

Nope!

wouldn't that show up as a check engine light or as a sensor fault when you scanned the computer? I recently it scanned and nothing came back as far as a temp sensor.

Never shows up.. It is doing it's job so far as the computer knows. Only thing is... it is lieing to the computer. So the computer takes this lie and can hardly run as a result..
Big JIm