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Discussion Starter #1
So, about 3 years ago I inherited a 1987 4WD Toyota pickup with a 22R, carb and a 5spd manual from my father as my first truck. He bought it brand new and used it as his work truck for 18 years; never gave him any grief. He retired the truck because of its high mileage (damn near 300,000 miles) and it failed emissions. Now since I have gotten the truck I have been doing my best to restore the truck to be my daily driver. I have replaced/rebuilt most of the drive train: Brand new engine, rebuilt trans and transfer case, DUI ignition, remanufactured stock carb, LCE header and 2 1/4 full exhaust, new fuel pump, new PCV, new air filter, new fuel filter, new sparkplug wires, sparkplugs (set to the proper gap) all new vacuum lines all around, ect. Now, I've gotten everything put back together so that the engine runs and the truck are almost ready to drive again.

This is where the trouble begins. Whenever I start the truck it will go to the high idle like it should and run for a couple of minutes. Then the engine's rpm's will gradually slow down, till about regular idle speed or so, and will start doing a chug...chug...die sort of thing. This happens, or it will reach that point and rev back up on its own (I wont even be touching the gas pedal). If the truck does continue to run though it just seems really rough. Recently the engine has also been going through a routine where it starts, but at a very low idle. Then it revs up a little on its own and stays at that speed, even if I step on the gas like to disengage the high idle. The engine has also deiseled on me a couple of times recently.

-I have tried adjusting the idle speed screw to no avail.
-The valve clearances are correct.
-Float level is fine.
-The electric choke is working.
-I cleaned the EGR vacuum modulator filters.
-All the intake manifold and carb mounting bolts are tight.
-All vacuum hoses are connected and in good condition.
-The timing was set to 0 degrees with all vacuum advance hoses disconnected and plugged.
-The HAI diaphragm had to be removed because of clearance issues with the DUI distributor and the vacuum line was plugged.
- I have checked for vacuum leaks, I could find any using spray carb cleaner.
-There are no blow fuses in any of the fuse boxes


The worst part about all of this is that the most of the troubleshooting has to be done with the engine running, and mine just will not cooperate. I have tried everything I can think of and this once joyful project has turned into an absolute nightmare. I have come to the point where I will probably tear all of the intake out, replace the EGR valve and vacuum modulator, and reinstall the intake manifold, taking extra care that there will be no vacuum leaks anywhere.

Please, if you have any information on why this might be happening please post it up. I’m just a 15 year old kid that is completely out of ideas.

 

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rock crawler
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The 22R has an Electronic Control Module for the emissions. It's possible that it may have a problem, or one of the many sensors may be going bad.
 

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I had a similiar problem when I bought my 87 carb'd 4x4... would idle rough and die after a bit. Turned out to be a bad electrical connection on the ecm.
 

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Discussion Starter #4
I have since verified that the timing is at 0 degrees. The idle mixture setting is set to 3.5 turns from closed, the HAI system was reinstalled, I replaced the corroded engine fuse, checked all of the ECM connections and I checked the fuel cut solenoid. It functioned properly, but the o-ring was out of its groove.


I then ran the truck again, and found that the intake manifold has a vaccum leak. So, I going to have to tear down the intake and replace all of the gaskets. While I have everything torn down, is there anything that I should look into replacing, other than gaskets?
 
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