Idle issues.

[orange1983ranger]

Hello again all, Got another question for you brainiacs. When the truck idles it doesn't do it consistently, it goes slow to fast in waves, warm or cold. The folks at autozone told me it was the throttle position sensor or air control sensor, but I can't find either one to save my life so I brought the truck to them. The guy came out and looked, then printed a few pages to help find them and no luck. I think those are for efi not carburetors. Anyway, I would like to figure out how to fix that and the starting problem. The starting problem is when I first turn the key it goes for a second then dies. I do it again and does a bit better but dies again even feathering the pedal. then it starts the third time and catches, runs a bit rough with my foot on the pedal for a couple minutes. While I am waiting for it to stay idling the speed increases the warmer it gets if I hold the pedal steady. When it's warm and I start it, it does fine. Ideas?

 

[RonD]

The 2.8l engines had carburetors, motorcraft 2150 carburetors

Google: Motorcraft 2150 2V Theory

The first link should have pictures of that carb with labels of all the parts

vacuum leaks change idle, warm or cold, on older engine the vacuum lines get brittle and crack, worth checking.

The choke operation can effect idle, it should close when engine is cold and then slowly open as engine warms up, this does three things, it increase vacuum to advance the timing and with increased vacuum more fuel is pulled from the jets, the choke "cam" will also increase the idle, although as engine computers were added they would increase the idle via a solenoid.

Having to restart a few times when cold could mean the choke is not closing, or not closing enough, so engine is not getting enough fuel to stay running.

 

[wildbill23c]

My choke isn't even hooked up, so mine has these symptoms every morning. I just start it up and keep my foot on the accelerator slightly for about a minute then drive away or it will just continue to die until it warms up. Mine will idle slightly high after its warmed up and haven't figured out why, if I adjust the carburetor it will eventually start to idle lower, but then the next morning its a pain to even get started. These old ranger's and bronco 2's with the 2.8L were pretty temperamental it seemed like because of the half ass computer-feedback carburetor junk that ford tried to jerry rig into these trucks.