Idle issue

[Cheford]

Hello All

Just wondering a few things;

1) When i start my truck, my RPM's sometimes are normal but every second day or so when i start my truck my rpms will drop to about 300 then up to 600 then down to 300 and then to 600 etc etc. once i put it in gear and drive a bit, the RPM's seem to calm down. could this be IAC/TPS? or both?

2) also RPMs are between 2500-3500 doing between 100-110km/h, i've been told that the high RPM's are due to a bad TPS/IAC is this accurate?

If any of this didn't make sense let me know and i'll re-write it.....it is 4am after all

 

[MrShorty]

Year/engine??

IAC is one definite possibility, and it only takes a few minutes to clean up.

TPS could also be in there, along with any number of other elements of the engine management system. 1st thing I'd do to check this would be to pull codes from the computer and see if the computer can see/has seen anything out of the ordinary.

 

[Cheford]

98 4.0l sohc