Hey all, I'm not sure where to turn so I appreciate any assistance. I have a '95 3.0 5spd that started running rough under any load. It had been sitting for many years (a couple of years ago) and I started driving it more recently. I replaced the fuel filter and found a lot of rust in the fuel line. So I had the tank and injectors swapped. It seemed to run fine when cold, but once warm it would sputter and stall at idle. I tried spraying carb cleaner all around and didn't notice any vacuum leaks. I could only do this while cold, once warm the idle would start to surge up and down or stall. I pulled the throttle body (it is surprisingly clean) and swapped out the TPS sensor (assuming I did this right, I set it to a center position). Now when I turn it on, the truck instantly rapidly surges between about 2800 and 3000 rpm. I also noticed the coolant was leaking after I reattached the throttle body so I probably just didn't get the back line on tight, i'll fix that. But once I pull the TB off again, is there anything else I should do? What should I be looking for?

Sincerely appreciate any help
Thomas Z
Austin, TX

 

That’s a lot of stuff to factor in: rust in fuel lines, time sitting, dirty fuel injectors etc.

if I were you I’d give the engine a fresh tune up including new oil filter, air filter, plugs, wires, distributor cap and ignition rotor. Also replace the PCV valve and check all vacuum hoses for leaks. Have the ignition timing checked as well just in case

USE OEM TOYOTA PARTS ONLY.

The TPS sensor only goes in one way. It shouldn’t need adjustment.

What does need adjustment is the engine idle on the throttle body.

You do this by finding the flathead screw on the TB and turning it L or R to set correct Idle.

Warm up the engine to operating temp and run the engine in neutral at 2500 RPM for two minutes. Set the idle using your tach inside the truck to as close to 800RPM as you can.
hope this helps 👍🏻

 

Thanks. I do have new plugs, wires, etc. What was interesting is as soon as i put the throttle body back in the engine was running at 2500+ rpm AND surging. I'll try idling it back down but i couldn't even give it time to warm since it was running so high. Is there another way to check for vacuum links that doesn't involve carb cleaner? I don't mind trying that again but i didn't get results. For the PCV valve, can that be done without removing the intake?

 

I highly recommend removing the Upper intake Plenum to get at the PCV valve, grommet and hose. Its not too hard, just watch some Youtube Videos on how to do it.
All three parts should be replaced as age and heat will have made all three hard and brittle. The PCV valve is important for proper idle, power and gas mileage.

BE CAREFUL, just trying to remove the ventilation hose can lead to it breaking in two.

While you're in there check the fuel lines and njectors to ensure they're in tight and vacuum hoses for any damage or leaks. With the surging TB, my only idea would be something on the TB called the AICV or Air intake control Valve. Its a spring assembly located on the right side of the TB that may be getting stuck.
Then again it could be an electrical or fuel problem. look on the forum for the AICV problem.

 

Ok, update. I haven't done the PCV yet. I had installed the TPS incorrect and that was causing my earlier problem. I fixed that and it drives great cold. But after the engine fully warms up the idle is jumping between about 500 and 800rpm (distinctive surge). It's also blowing a little black smoke (rich maybe?) with the surges. I sprayed some carb cleaner all around and didn't hear the engine change at all so i'm pretty sure it's not a vacuum link but i'm happy to try again. Before I pull the intake to do the PCV is there something else that I should hone in on? That's a big job.