Little bit of Idle Trouble

[Coastiekid]

Hey guys,

I've got a slight problem with my 1993 4Runner, it's a SR5 V6, 5sp Man, 4x4, P/S.

So here's the situation: After startup, engine runs fine, the fan starts up and runs for about 2-3 minutes, or until warm-up, idle is good and stays normal. Driving in gear she runs fine as well. It's when i'm driving at pretty much any speed and take it out of gear to make a stop. As the engine returns to idle from any rpm, with trans in neutral, the engine will drop to about 500rpm or so, and bounce between 450 and 550rpms for approx 10-15 seconds, or until the vehicle stops. I think when I stop, the motion is jarring something into place and idle returns to normal operation, about 750rpm. This has been happening ever since I got my valve cover gaskets replaced.

I've talked to a mechanic and he thinks is the Idle Air Control Valve, or possibly something wrong with my throttle body. My dad and I have checked the dashpot to make sure its properly working, and the spark plugs, wires and dist. cap are all new. I've exhausted most other avenues of approach to fix this problem, thus, I am here.

Can anyone give me an idea on how to fix this problem and if it is a major problem?

Thanks,
Coastiekid

P.S. I'm glad i found this place, becuase i absolutely love my 4Runner, and i'm really happy to know that there is a fan base for them! Look forward to chatting with you guys.

 

[Coastiekid]

If Anybody could help, it would be greatly appreciated.

 

[Hyde802]

Sounds like a vacuum leak. Make sure all hose connections are tight.

Is it throwing any codes?

 

[purevenom1]

Could have vacuum lines in the wrong place if the valve covers where changed or one not installed. Find a vacuum diagram and trace all the lines back to make sure they are in the right location.

 

[4runner_kid]

Check the PCV vacuum hose on the passenger side valve cover.

 

[Coastiekid]

Ok, I'll make sure i check all the hoses. How would i know if one is slightly off, will it be making a sound? or is it just a visual inspection?

 

[Coastiekid]

Also, i was talking to my dad and he said that it might be a leak between the intake manifold and the block, and might need a new gasket, does this sound possible? and if so, how much would replacing that gasket run me? doesn't sound cheap.

 

[T-Dubya]

to check for a vacuum leak get some brake/ carb cleaner, starting fluid, etc. spray a little around vacuum connections while running. any leaks the idle will change. be caefull not to spray around ignition parts too much. could spark a fire.