1998 3.0 4x4

[woody9907]

I have this truck and it will start fine and drive fine. But then sometimes it will just idle rough as heck like it is hardly getting fuel. I have 60 psi fuel pressure put in a new fuel filter. I even have it at a mechanics for a diagnostic but it is not throwing any codes. it will be running fine one minute and then all of a sudden it starts this. mechanic can not find any problem as of yet and it has been 3 weeks. what kind of gremlins am I looking for?

 

[Uncle Gump]

@woody9907

I moved your post to the 3.0L forum... it will get better looks there and it is the help forum.

Please feel free to go back and introduce yourself in the introductions forum.

 

[RonD]

Welcome to TRS

Not alot to go on
How many miles on the vehicle?

3.0l Vulcan engine was very reliable but did have some common issues that can come up

Clean MAF sensor, always, when there is a engine stumbling issue
Check or replace PCV Valve, every 4 oil changes, every 3 over 150k miles, sticking PCV Valve can cause intermittant vacuum leak at idle


On the top back of the engine is the Cam sensor and synchronizer, the synchronizer often needed to be changed every 100k miles, and can cause what you describe

The coil pack has 3 coils inside, each fires 2 cylinders, if one of the coils starts to fail(2 cylinders misfire) that can also cause what you describe

Yes, you would expect codes for these, especially after 3 weeks

So....................it could be an issue with the computer

For $15-$20 you can get a Bluetooth OBD2 code reader, it works with a smartphone, free APP, or $5

With this you can SEE Live Data while engine is running, you see what the computer sees
So you can look at different systems to see if there are changes when engine starts to act up

These work on ANY vehicle, 1996 to 2021, so not a Ranger thing or even a Ford thing, any vehicle sold in North America, so a good tool to have

 

[woody9907]

it has 205,00 miles on it.

 

[woody9907]

the problem is that it will be running/idling fine and all of a sudden it will do it. It does not do it all the time. But when it does if you pump the gas pedal it will pick up, but in the process it will back fire and pop. Then it will run just fine. I have 60 psi fuel pressure, a new fuel filter and a new mass air flow sensor and throttle position sensor.

 

[RonD]

Coil pack or Cam synchronizer fits symptom, as would computer

I would remove coil pack and give it a good look, looking for small cracks
examples here

https://www.taurusclub.com/attachments/cracked_ignition_coil-jpg.55195/

https://www.taurusclub.com/attachments/coilpack_cracked-jpg.148977/

https://www.taurusclub.com/attachments/coil3-jpg.101937/

Ford Taurus used same coil pack and they seem to take more pictures that the Ranger guys do, lol

 

[woody9907]

Well we finally found out what the problem was. mass air flow sensor(faulty brand new) faulty IAC(New) and the shaft on the throttle body is worn out found this by doing a smoke test. Replacing them as we speak will give update when done.