Outer Limits 4x4 Board

Hey guys I have a 4.5 80 series and every few weeks for about 4 months it will idle at around 400rpm instead of the usual 700 or so. When it is started it will rev up like usual then drop rapidly to 400 even when cold. It doesn't seem to lose any power, it just idles really low and rough and usually last for a couple of days. Also, it has never began doing it when completely cold, only when started after recently driven. Has anyone had this problem before? Any help would be greatly appreciated.

sounds like the computer goes into limp mode so you need to do a diagnosis on the computer and check for codes .

ive had this problem and it progressively got worse. i discovered that their were intake leaks on the engine side of the air sensor, meaning it was getting un-metered air! my intake hose and the two breather hoses were perished, after i replaced them it fixed the problem - ideally, a leak test should have been done but replacing the three hoses helped.

hope that helps you, dave.

Thanks guys, I got it put on the diagnostics machine today and it didn't put out any codes. The mechanic seemed to think it was the stepper motor from the ECU which controls idle speed and apparently build up with carbon so he cleaned it up and now its idling fine. Hopefully it has fixed it for good but only time will tell. If this doesn't fix it ill be looking for air leaks. Ill keep you posted.

Cheers

Reagan

know reagen
you should have known that as you do work for toyota hahaha
cheers jason

Cleaning the idle speed controller usualy fixes the problem. No good looking for vacuum leaks as there would be an increase in idle speed if there was any.
Rob

roblrc wrote:Cleaning the idle speed controller usualy fixes the problem. No good looking for vacuum leaks as there would be an increase in idle speed if there was any.
Rob

x2, had the same problem, got the idle speed motor cleaned, Reset ECU and gave it a tune up and runs like a dream!!!

I had a similar problem a while back. Idled so slow it got lumpy. Whatever it was it sorted itself out and is now back idling as normal. Go figure