94 d21 4cyl high idle/jerky low throttle driving

[EstoMax]

Hey Guys,

my 94 d21 4cyl is having some funny problems, the idle usually sits around 750-850, but recently it has started jumping up to 1400-1500 rpm when i come to stop signs and holding there. About 60% of the time it does this, the other times it will settle down to its normal idle. I am guessing that also related to this issue is if i cruise around under 2000 rpm in low speed traffic and hold the throttle in one place then the truck jerks a bit like i was closing and opening the throttle plate constantly.

I am guessing it has something to do with idle adjustment but was wondering what you guys did to fix it when it happened to you
cheers for input,
Marko

[seang]

Idle air control valve? I'm not 100% sure.

[EstoMax]

thats what i would suspect, i havent cleaned it yet, but i wanted to see if this is common or not. i suppose ill pull the idle control valve off tomorrow and do a thorough cleaning

[silveradobeast]

you know my truck idles at 1500 all day and jerks somethimes but its rare so this past winter i messed with the idle adjustment and lower the idle and then my truck wouldnt start so i just put the idle back to where it was it seems like is a common problem
let me know if you figure it out

[waynegarcia13]

Easy way to test the idle air control valve if you do not have a scanner is to remove it from the throttle body, leave it plugged in though, turn the key off and on to see if it moves in and out then try to start the truck if there is no movement or it is fully extended replace it.

[Desert Rat]

Look for vacuum leaks, cracked hoses, etc.