Got a horrible idling issue going on...

[BigSur]

I have had a bad idle problem for the last few weeks and i can't get a grip on what the heck it is. She drives great and i am getting great gas mileage (13-14mpg) but when i come to a stop she will idle rough and the tach needle will move ever so slightly between 650-700rpm's. Now i have looked under the hood while the truck is running and i can't hear a hissing sound (like a vac leak) so i am a lil' puzzled. I have heard alot of people talk about the fuel pump so would that effect my truck while i am stopped? I have also done a complete major tune-up and that didn't help either. Could it possibly be ERG valve? What about a carb mixture problem?

Any help would be great...

 

[swank60]

I wouldn't mess with the idle mix just yet - did you order your FSM for the emissions manual?

I had this problem a while back, but it was really limited. I was working on about 8 other things, it came up for a while, then went away...but it was vac related. For some reason I'm thinking that what fixed it was cleaning that three nipple vac manifold on the intake manifold in front of the carb. Or maybe it was a few of the vac lines on the dizzy side of the breather were unhooked...but it was vac/emissions related...but then again, just about everything with my truck is...

 

[wildman4wheeler]

i had the same thing my problem was fuel fillter. cha ching bought a new one and no problems

 

[Tinker]

Spray carb cleaner around the base of the carb & the top of the intake manifold where it meets the head (use the snorkel tube). You'll have to take the air cleaner housing off to get to the manifold. If the idle picks up, you have a vacuum leak. I've tried re-torquing the manifold bolts on both my FJ60s to no avail (even had a bolt that was clear out on the '84 I just bought).

I used a SOR gasket on my '83 & it sealed up the manifold leak - it's thicker than stock & most aftermarket.

 

[hj60]

I'll second the SOR manifold gasket.
There are other vacuum leaks I had to track down, including one on the
carb.
I ended up just rebuilding the carb, doing a tuneup and replacing all the
vacuum hoses and any malfunctioning/broken emissions valves. I also
cleaned out my EGR tube. Runs 150% better now. 12.5 MPG on Phoenix
gas (not the best in the US.). I'm also not on the freeways much.
I have 3 more emissions valves to replace and about 2' more of vacuum
hose and I should be all good.
Also, per Mark Whatley, shine a light down your throttle body. If your
manifold is cracked, that could be causing the rough idle as well. He says
it's usually repairable by a competent welder. Check recent Toyota Trails
for the article.
Also, thanks for the P/S pump bracket. I haven't had time to put it in yet, but I got it safe and sound. Definately appreciate the inclusion of the hardware.