Fussy idle on 1999 4JX1

Joined: Apr 26, 2005 Posts: 2

Hi all, hope someone can help me out here.
My truck has a 4JX1 engine which has had all the injectors done under the recall etc. I've noticed recently that the idle isn't as smooth as it used to be and the revs jump around a bit in the 1000 rpm range. Seems a very small amount of throttle makes the revs jump. From 1200 rpm or so, the engine is as smooth as silk and the power is still 100%.
I can get the engine to do the same thing by manually lifting the throttle under the hood.
I suspect a crook throttle sensor sender or receiver, but if anyone else can shed any light on this, I would be most grateful. All vacuum lines appear to be connected and the electrical plugs have been pulled apart and cleaned as well.
Has the correct oil, new filters and fresh battery.
I've also had the computer checked for error codes but none show up.
Thanks in advance

Joined: Jul 26, 2007 Posts: 5 Location: ireland

hi .there is 2 vacume pipes at the egr valve clean out the lower one make sure you can push a 1/8 rod about 3 to 4 inchs into the manifold and check your oil level is full and not low or over full.also check the injector wiring harness connection at the dip stick is not full of oil if so use some contact cleaner.