u/BiggieF1

Hi all! I've been battling this issue for a while now. My 98 Hilux (I know, not a Taco, but the pickup subreddit didn't want anything to do with mine) runs at 1600rpm at operating temp. I've replaced the IAC valve with a new OEM one, cleaned the throttle body and replaced all the gaskets for the intake.

It's clearly not a vacuum leak, if I pinch the IAC hose and starve it of air, the engine dies.

I've checked the ECT sensor is working and it is, as I've cross-referenced it with a 01-04 2RZ/3RZ-FE Tacoma FSM and it follows the ranges as it should.

I've done the IAC relearn procedure after disconnecting the battery several times at operating temp and it still doesn't lower its rpms.

The throttle plate is completely closed and the cable does have some slack, so it's not pulling it open allowing for more air to come in.

Checked the TPS is reading correctly and it is, with an OBD2 scanner it shows the throttle is at idle position.

If anything, I'd like to ask if anyone knows where I can find more service manuals to keep diagnosing, since the Tacoma one I found has some different components, like the TPS.

I'm on the fence on the MAF sensor reading and the position of the vacuum plunger set screw, since this truck has been passed around mechanics and it may have been tampered with.

Thanks in advance!

Hi all! I've been battling this issue for a while now. My 98 Hilux runs at 1600rpm at operating temp. I've replaced the IAC valve with a new OEM one, cleaned the throttle body and replaced all the gaskets for the intake.

It's clearly not a vacuum leak, if I pinch the IAC hose and starve it of air, the engine dies.

I've checked the ECT sensor is working and it is, as I've cross-referenced it with a 01-04 2RZ/3RZ-FE Tacoma FSM and it follows the ranges as it should.

I've done the IAC relearn procedure after disconnecting the battery several times at operating temp and it still doesn't lower its rpms.

The throttle plate is completely closed and the cable does have some slack, so it's not pulling it open allowing for more air to come in.

Checked the TPS is reading correctly and it is, with an OBD2 scanner it shows the throttle is at idle position.

If anything, I'd like to ask if anyone knows where I can find more service manuals to keep diagnosing, since the Tacoma one I found has some different components, like the TPS.

I'm on the fence on the MAF sensor reading and the position of the vacuum plunger set screw, since this truck has been passed around mechanics and it may have been tampered with.

Thanks in advance!