my tow rig is acting up and driving me nuts. when i start it cold it runs real rough. idles up then damn near dies keeps doing this till it warms up a bit. going down the interstate the check engine light pops on and the miliage really sucks. it brings up a lean conition on the computer as a code 44. wide open throttle is fine runs like hell. it is eating gas at about 6 to 7 mpgs right now empty at 65-70 mph. o yea its a 89 chevy crew cab dually with a 454 4 speed. any new ideas would be helpfull. i have changed out the o2 sensor, the tps, the egr and put in a set of plugs, cap and rotor. just running out of ideas on my end. mike

Mike,
you may way to swap out your fuel filter and check the spray pattern of the injectors in the throttle body.

$.02

HTH

john:beer:

Don't know if I am using the right terms, but it might be the "idle motor" It opend and closes a "gate" to allow more or less air in the throttle body when cold. The area that the air passes through it the triangle on the pass side of the TB, towards the back of the unit.

Thats my guess, I could be way off, though:)

If it seems like it might be a vacuum leak problem, replace
the TBI base gasket at the intake. They are known to fail from time
to time and start leaking. The idle will be erratic and the
problem may come and go with temperature.

Let us know what you find.
Jay

well thanks for some more ideas, i have already put in a new fuel filter and checked the spray pattern. i have checked all over it for vacume leaks. this damn thing has got me baffled, and pissed. i will check out the idle motor or what ever it is called. thanks mike

It's called a "Idle Air Control" (IAC) motor (also called a valve)...it is a stepper motor.

It's the one that threads into the throttle body, behind the TPS, on the same side.

Charly

Just another note....don't spray carb cleaner on the IAC as it will damage it.
Unscrew the IAC from the throttle body housing and you can check and clean the
little needle seat in the throttle body housing. ALso, don't push or pull on
the IAC solenoid once you remove it.

Jay

gunracer1,

Did you fix this problem, im having the same problem, I would like to know how you fixed it. Thanks

My TBI did this exact same thing and it was the fuel pump, to low of preasure. Changed the pump and it ran like perfect again. Also have you tried unpluging the IAC yet? Let it idle then pull the plug on it and see if it stablises the idle.

Originally posted by USFSIHC
My TBI did this exact same thing and it was the fuel pump, to low of preasure. Changed the pump and it ran like perfect again. Also have you tried unpluging the IAC yet? Let it idle then pull the plug on it and see if it stablises the idle.

Where is the IAC?

Originally posted by K-Rigg
gunracer1,

Did you fix this problem, im having the same problem, I would like to know how you fixed it. Thanks


He made it worse, he bought a DODGE!:D :flipoff2:

Originally posted by K-Rigg


Where is the IAC?

Its right behind the TPS on the right/passenger side Of the TB.

Gota Chiltons Manual? Page 4-23. Also if you do unplug the IAC and your Idle becomes normal does not necessarly meen you have a bad IAC make sure you test it before you buy a new one. I know that my truck would run better with it unpluged but the root of the problem was the fuel preasure being to low.

My truck will die when i turn on the AC, What does this make it sound like? I'm going to unplug the IAC and see if that helps.

Well i unplugged IAC and it ran normal but when i turned on the AC it kinda had a hard time but ran fine after wards. Also my truck seems to cut out on hills and is very hard to start, would this be caused by fuel pump or this sensor?

Originally posted by K-Rigg
Well i unplugged IAC and it ran normal but when i turned on the AC it kinda had a hard time but ran fine after wards. Also my truck seems to cut out on hills and is very hard to start, would this be caused by fuel pump or this sensor?

My first guess is the fuel preasure. I would start by testing it then move on to testing the IAC. TBIs like 13 to 17 PSI the books says 9-13 but mine wont run for shit under about 15.

Well ill probably end up just changing the fuel pump anyway because the truck has 150,000 miles on the stock one. Will driving with the IAC unplugged hurt anything for a short period of time?

Originally posted by K-Rigg
Well ill probably end up just changing the fuel pump anyway because the truck has 150,000 miles on the stock one. Will driving with the IAC unplugged hurt anything for a short period of time? Nope.

i sold that gas guzzling pos and bought a dodge diesel. 17mpgs and 4x4 to boot. i never did get the damn thing sorted out. sometimes it was fine, other times it was terrible. mike

Right on I bought a 02 4x4 Dodge Cummins about a year ago and I love it. Hauls my shit awesome, unloaded on the highway I get 20 MPG! My record is 22.5 MPG at 55 MPH

Originally posted by gunracer1
i sold that gas guzzling pos and bought a dodge diesel. 17mpgs and 4x4 to boot. i never did get the damn thing sorted out. sometimes it was fine, other times it was terrible. mike

That is the first smart thing that you have done... :flipoff2: