You're confident it's the IAC? It makes sense to me, but I just want to be sure. I guess I won't know until I repair or replace it.

Did you have to get a new valve or was yours repairable? There's not a lot to an IAC. I wonder if they're repairable?

They are super expensive at the dealership new.....does anyone know of a good source for a more reasonable part?

 

On a fuel injected engine, your cold start injector will add more fuel to the intake manifold untill the coolant reaches a certain temp which is noted by a coolant temp sensor. If you drive on the highway while your CSI is still active, your going to have a super rich condition which will cause low power levels and possibly surging, miss firing ect. It takes my truck just a few minuites for the CSI to shut off from a cold start. If that sounds liek your symptoms, let it warm up to normal operating temp before hitting the highway (which you should anyways). Or a coolant temp sensor could be worn out/corroded. Even a low coolant level can cause this as your sensor won't pick up the proper temp and may cause your CSI to keep adding fuel all the time. Oh the joys of fuel injection.

 

Which temp sensor does the CSI get it's information from on my 2000 4runner with the 3.4L? I believe there are two? One on the back of the engine that sends information to the gauge and one on the front that send info to the ECM? Is that right?

My 4runner seems to take an exceptionally LONG time to warm up. I can run it (even in the summer) for 6-9 minutes before it finally idles down and is ready to go.

Temp sensors are cheap and easy to replace so I may start here. Keep the ideas coming! I may get this fixed yet!

Thanks for the input so far!