Engine bogs when starting, rpm's stay high between shifting- HELP!

[kyle92008]

Ive got my brothers 98 Ranger 3.0 manual 4x4, that Im trying to fix while he's in Iraq.

The problem is that when you start it for the first time in the morning it will usually start all bogged down for a second and die, then starting it again, will start up all bogged down on the verge of stalling for 2-10 seconds, then the idle jumps up and it starts running fine.

It only does this on the first start of the day, or if you don't start it for 8 or more hours.

The other problem is that when youre driving it and then take it out of gear, the rpm stays up at where it was when you were in gear, and doesnt return to normal idle until you come to a complete stop.

I got 2 codes off the computer: 171 & 174.

Both are: Air/fuel ratio too rich/lean for PCM to correct.

Ive cleaned the Mass air flow sensor and replaced the Idle Air control valve, and nothing has really changed.

Any help would be musc appreciated-
Kyle

 

[Wicked_Sludge]

you have a vacuum leak.

 

[kyle92008]

thats what I figured, but I have no idea of where or how to find it-

 

[Wicked_Sludge]

with the engine idling, useing carb cleaning or starting fluid, spray around all hoses and gaskets. once you get a sudden change in RPM, youve found your leak.

 

[kyle92008]

Cant find leak-

Ive been all over the engine with carb cleaner, and the idle never seems to change-
Is there anyting else that could be wrong with it, or another way to test for a vacuum leak?
Thanks

 

[skippy]

Ive been all over the engine with carb cleaner, and the idle never seems to change-
Is there anyting else that could be wrong with it, or another way to test for a vacuum leak?
Thanks

you may have vacuum operated a/c controls under your dash,you might check for a leak there as well.fwiw

 

[kyle92008]

no a/c

theres no a/c on the truck-
although there has definately been some malfunctions with the vent/air controls in the cab.
How would I go about testing, if this is the culprit-
thanks

 

[skippy]

theres no a/c on the truck-
although there has definately been some malfunctions with the vent/air controls in the cab.
How would I go about testing, if this is the culprit-
thanks

well thats a good one,don't want the smell of spraying chemicals in the cab,so with engine idling pinch off any and all vacuum lines one at a time and see if the engine reacts.don't crush down to hard.thats what i'd do,but my controls are the old cable type.happy hunting.