Rough Idle Update

[Quiksurf]

From a techinician that can actually fix a truck

first off no baro sensor on that vehicle it is a calculated value that relies heavily on maf but not soley. skewed baro readings can be caused by vacuum leaks, exhaust restriction, misfires etc. not likely maf issue, not likely pcm issue. if you have no codes stored, it might just be a sensation. attempt to nuetralize engine, trans, and exhaust. loosen (do not remove) engine and trans mounts and exhaust fasteners. veh drive and rev. leave in neutral, retorque fasteners, exhaust last. the dealers scan toolcan fow test fuel injectors on obd2 vehicles without removal. compares pressure drop to ms of on time of injector. mode 6 data ( the dealer should know how to read it) will show any history of misfire information. lean conditions can cause a rough idle, but an 02 sensor would trigger a check engine light before you would have a rough idle concern, static compression tests do not always reveal valve train issues. running compression tests are much more accurate when testing valve train issue.

as far a the lean issue, how lean long and short fuel trim values?? going into closed loop? are you hoping the idle surges when spraying god knows what at the intake. get a mechanic with a good scan tool and understanding of how to test for vacuum leaks with artificial enrichment monitor o2 readings not idle surge. if you still feel that there is a vacuum/ unmetered air leak have the dealership smoke test you intake and airbox.



AND MOST IMPORTANT............

ITS A F'N TRUCK. NOT A LEXUS.

 

[Blackedge03]

AND MOST IMPORTANT............

ITS A F'N TRUCK. NOT A LEXUS.

This statement would be appropriate if I were comparing my truck to a lexus but I am comparing my ranger to other rangers with the same engine. I have been driving trucks for over 30 yrs. and while I am not a trained mechanic I know when a vehicle does not idle correctly. As far as all the technical references in your post, that is why I reluctantly took it to the dealership because I don't have the expertise to deal with it. My truck has been checked by one of the best mechanics around with over 30 yrs. experience working on Fords. He wasn't able to fix it and somehow I don't think you could either.

 

[Rearanger]

My FSM says barometric sensor unique to supercharged engine. I guess the MAP does that job as well as denser air will cool it faster as will cooler air, so in the end it is the same thing.

I wonder if there is drag somewhere on the engine that will show up as the idle you describe.

After this it gets complicated as I guess the best way now would be to pressurize the intake/exhaust (if that's possible) and use smoke to see any leaks.

I'm not a computer guy but for the PCM to be reading the signals wrong would mean that the programmed parameters are incorrect.

Quiksurf, glad to have you confirm my posts - from a shade tree mechanic that can actually fix a truck as well.

 

[Quiksurf]

3.0 L 2v motors are not inherently a smooth running engine. any person who calls something a quiver in the engine and is concerned about it i think is being a little too sensitive to the engines normal vibration. dont forget the internal combustion engine is just what it is named. Controled explosions transfering chemical breakdown to a physical movement. no computer control can cover as many variables as the world throws at it. i guess i should have said don't be over critical of a slight "quiver" (your word not mine) at idle, there is likely no way to change that and there is not likely anything actually wrong with your engine.

sorry but you need to be realistic with your perception of how an engine should run.

btw did the dealer mechanic fail to fix it or find nothing wrong with it?

 

[Blackedge03]

The dealership said that it definitely has a rough idle AND it is running lean AND the truck "thinks" it is 4000 ft. higher than it is. They said that the 3.0 L is normally smooth. They said if it had been a 4.0L they would have sent me on my way and not taken my money. They went to the trouble of reflashing the computer. They kept the truck all day trying to figure it out. A local mechanic said that it is not right and that the 3.0L should idle smooth. I had a couple of my friends check it out and they said it is not right.
As I said before, I have been driving trucks for a long time. This one is not right. Now it may have been this way from the factory but if it was it should never have been shipped. If I ever get it fixed I will let everyone on here know. Maybe it will help someone else out.

 

[coffee]

My 3.0 runs smooth as silk @ 800rpm. Looks like everything has been check. Any chance of a collapsed lifter?

 

[irishblessing]

my 4.0 idles smoothly for a truck with 156k its tip top

 

[dirtsquirt]

I had a problem with a ruff idle, chased it for a couple weeks, one day i was low on gas so i stoped at a different station then my normal spot, ruff idle went the way of the dodo bird, filled up again at my normal spot ruff idle returned. So i added some octain booster and it cleared up again, it might be your fuel station? i will not get gas there again.

 

[Blackedge03]

Traded it in for a new 2009 Ranger XLT Supercab.

 

[96Greenster]

Traded it in for a new 2009 Ranger XLT Supercab.

Well, that solved your problem...

Out of your way and out of your life

Good Luck with the new one...