erratic idle, vacuum leak, timing all over the place

[rib256]

Dusty, this is a little metal tube under the fuel rail on the left. As you are looking at the engine.

[EvilcowRoland]

It's the lower vacuum source on the 1-piece intake manifold. It's an L-shaped tube.

[patrickjengram]

If creating a vacuum leaks helps it idle better, than you should look at what the computer uses to create its own vacuum leak, the idle air control motor. Clean the passages in the throttle body. Clean the pintle on the iac, being careful not to turn the pintle. Might need to replace it. If you had a scanner, you could see the iac motor counts to verify this.

[EvilcowRoland]

I thought about the IAC, but you can hear it moving when the key is turned on. Of course it could be loaded with carbon too. Next chance we get, we'll try cleaning that and see if it helps.

With the engine idling, if you unplug the IAC or the TPS, what should the computer do? When we unplugged them, nothing happened. It kept on idling in limp mode. I thought that was really strange.