Qbert

1992 4RUNNER 4X4
3VZE
5Spd manual
just rebuilt (450 miles on engine)

Can someone please help me out here on this issue.
I just replaced my heads again on my newly rebuilt engine (Machinist screwed my valve adjustment badly) and now I developed a new problem.

Engine idle great at 750 RPMs when warm and then when I drive it, it sticks at 1200 to 1600 RPMs between shifts and at stops. When I hit the gas pedal (slightly) it drops down to about 500 RPMs then settles back up at 750 RPMs.

I have searched and some folks say its the TPS, some say water temp sensor and then some say air pockets in the coolant system that is getting trapped underneath the throttle body. Anyone of you all experienced this or have a solution?
Your advice or remedy would be greatly appreciated.

wyoming9

iTrader: (1)

I would say look at your throttle linkage if it is not hanging up at the throttle body.

Perhaps cable is about to fail.

With the cable disconnected at the throttle body when moved by hand it should feel smooth as it moves

I just had a issue were mine did the same thing the throttle pedal mounting just broke where it attached to the firewall

The fact it goes back to normal when you blip the throttle says it is in the cable or linkage.

You have cleaned the inside of the throttle body and lubed the linkage during all the engine work??

Qbert

Yes I cleaned the throttle body inside and out. I didn't lube the linkage or spring because i was told that it will collect deposits and start sticking. I will go out today and check the cable and give it a small amount of lube.
Thank you

wyoming9

iTrader: (1)

I guess that might be a problem if your in the desert and get that real fine sand dust that gets in every thing.

I spray my linkage at least every oil change if not more often

Qbert

I burped my system like one of the threads suggested to by loosing upper radiator hose and turning it straight up then add distilled water. I also removed the forward water hose that goes under the throttle body until coolant came out of it. I also did the same to one of the heater hoses. My throttle now responses as normal. Hopefully this is the long term fix, I am still having issues with my motor running warmer than usual "1/2 to almost 3/4 of the way on my gauge". when I shut her down it sounds like steam is going into the over flow tank.
Another darn issue

millball

It is possible to put the head gaskets on the wrong sides.
There is a left hand and a right hand one. The water passage holes are different in them.
The engine will run hot if the head gaskets have been interchanged.

Qbert

no I did it correctly, double checked with the packaging and also made sure the forward driver's side water passage was not covered.
The story behind my engine rebuild was I foolishly put stop leak into my system. I replaced 80% of all my hoses and flushed the heck out of my radiator. I am thinking while the 4 days I was not running my vehicle some left over residue manage to harden up and is effect my radiator flow. I am thinking of pulling my thermostat to see if the coolant flow increases.

Qbert

According to my temp gauge it isn't over heating and the forward and aft heaters put out monster heat. Isn't that the sign of a bad thermostat or poor flow due to a blockage somewhere in the system?

wyoming9

iTrader: (1)

Most often with a bad thermostat you get no heat.Best way to check a blocked radiator is with a infra red heat gun.

The dash gauges are not all that good due to the degrading of the sending units from old age.

A bad radiator cap allowing the system to build to much pressure can cause issues as well

Qbert

Thanks wyoming9, I am going to go purchase a new cap right now and also maybe have the radiator flow checked today.