Hey all,

I have a 2000 t4r sr5 v6, no cel.

When I start it cold, it will run at about 1000rpm for 10 seconds, then slide down to about 600 at a rough idle (almost dying). About 1 min later, the rpm's start increasing and end up at about 1100 or 1200. Essentially, the truck runs great after the high idle kicks in about one minute after starting it. I do have to kind of milk it along (giving it a little gas) until the rpms go up.

One note, it doesn't matter if the truck is in neutral or park, still rough idle.



New MAF on 10-5-12, New o2 sensor, front bank, had cel, this fix the cel light. no change in idle


All the spark plugs and wires are new and gapped. 11-06-12, no change

Did sea foam on 11-08-12, no change

I took out the Air Idle control sensor and cleaned and tested it. 11-12-12, it ran just a little better for one or two starts, then went back to the original description.

I put a new TPS sensor in. 11-15-12, no change.

Can anyone give me some suggestions.

thanks

kevin

Does the truck run fine after a few minutes or does it high idle all the time?
Does it do it every single time you start it?
Check for vacuum leaks.
this thread says he replaced his IAC and it fixed it:
Fast Idle Problem Solved - Toyota Nation Forum : Toyota Car and Truck Forums

Does the truck run fine after a few minutes?

Yes.

or does it high idle all the time?

No. After the high idle kicks in (1-2 min), the idle eventually goes down and idles normally after it warms.


Does it do it every single time you start it?

Yes.

Check for vacuum leaks. I did. Found none.

does it matter if the engine is already warmed up?

Only runs rough on cold starts only, into a 10 min drive, runs great, idles great.

kevin

are you loosing any coolant? maybe a HG problem and seeping when its cold.

also what about a slow EGR valve?

I just got back from a 1500 mile trip and I kept a close eye on my fluids, and I did not use any oil or coolant. Whew..

I will give the egr valve a look in the next couple days.

thanks for your replies.

kevin

There is no EGR on the V6, just 4cyl.

Have you cleaned the TB?

It may be a leaky fuel injector that is dumping too much fuel into the mixture when cold.

What brand of O2 sensor did you use to replace the old one?

You could always perform a compression test and see what the numbers show.

I had a similar problem on my 1999 SR5 - had the Coil Packs replaced and the problem went away.

*this work was performed by my local garage - I am by no means an expert on these things.

Yes, I have cleaned the TB and the Air Idle control valve.

Bosch.

Thanks

kevin

i'm having this issue too now, on a 2000 5VZE Automatic, what was your fix to this problem? Thanks!

anyone ever solve this? Happening to me after big 3 & cs144 upgrade. after the truck is warm, cranks right up and idles fine. Only happening occasionally on cold start. Interior lights dim & idle speed drops to below 500 rpms and almost dies.

After that initial hiccup, idle speed is over 1000rpms and voltage showing 14+


Thanks in advance!

My issue was the fuel pressure regulator after i'd done the ISR mod, wasn't getting enough fuel since the FPR wasn't getting the correct amount of vaccum. I drilled a hole into the metal tube used for the ISR and plugged a vacuum mount nipple into it, voila, she's got WAY more power now, no more idle issues.

Thanks man. Vaccum issue here also.... just had one of the hoses from the charcoal canister( the vent that plugs into the frame). Glad this forum was here to help me diagnose. Another win for the toyota brotherhood.