that works the same way with my ford(3spd diesel) except when i'm pulling 15k lbs.

either way i get 12m/g with my dakota so i pay little attention to how i drive with it because i used to drive her every other weekend.

 

I get about 8-10mpg with my 3.9L-LA it sucks I would improve my mpg with a Magnum V8 probably even a 360 would do a little better?

 

my 93 was a v8. i got 23m/g running a 250mile trip on the highway and about 18-19 in town.

 

I just tried this, I disconnected it then started the truck (haven't started it today) the idle went up really high, so I plugged it back in and the idle went right back down WITHOUT THE IAC EVEN MOVING! This to me says there is something else controlling the gas? Obviously the air and gas levels control a stable idle and the IAC only controls the air so what controls the gas? Wouldn't the air:fuel ratio be thrown off and it would lean out? Sorry if this sounds retarded I work on small engines.

Since the idle goes up without an IAC reading and the idle goes down with a reading does this flag a vacuum leak??

 

something is definitely wrong then. with it unplugged it shouldn't have run without slight turning of the bolt pushing on the throttle.

 

I have that bolt turned all the way in too. Someone told me there is another stopper screw on the TB that controls the butterfly valve which is the true idle setting.

 

this?

i've been all over my throttle body since i got the truck and never noticed this till now.

this one looks like it'd have to be drilled out

 

I can't make out what I am looking at, have to be drilled out you say? I'm going to have to take a look at mine tomorrow.

 

right in the middle of the pic. at teh bottom is the arm from the iac and you can see the spring for the throttle

 

Now I see what your talking about, the thing in the red circle?



Is this how you adjust the idle?



I stuck my thumb between the IAC plunger and the throttle cable mount, it drove the idle way up then I watched it pull the plunger way in and bring the idle down...pulled my thumb out and the engine almost died then the plunger brought it back to idle. This tells me the ECU always brings it to a set idle so I'm wondering how that screw would even set a new idle speed?