IAC Valve Power Problems

[MattsMSP]

Yep, the upstream sensor. It was in pretty rough shape.

Idle: About 5 seconds after starting the car, it slowly goes lean and then back to normal on the Wideband. Usually when it does that is when it tries to stall out, but instead now it sounds like a quick miss fire and it's fine (no RPM drop).

 

[31R]

Good to know! Did you go with OEM replacement or OE type? Rockauto.com has tons of options and prices ranges from 28 to over 100. This is MSP specific too.

 

[MattsMSP]

Good to know! Did you go with OEM replacement or OE type? Rockauto.com has tons of options and prices ranges from 28 to over 100. This is MSP specific too.

I went with the OEM Denso replacement from RockAuto. Perfect fit and I didn't have to screw around with soldering wires

The stalling problem on warm starts is back. Whatever is causing it seems to be erased when I reset the computer and eventually gets relearned. I did discover, though, that I can't rev the engine between 2k -2500 RPM - I get to 2k in neutral and it just skips over that range. Could a faulty TPS cause both of these?

 

[31R]

To be honest i'm not sure....this seems kinda odd. If I find something i'll let you know.

 

[MattsMSP]

To be honest i'm not sure....this seems kinda odd. If I find something i'll let you know.

Agreed. The local Mazda guys haven't been able to track it down either, so if you have any ideas, please shoot them my way

 

[MattsMSP]

Not to revive this, but if anyone stumbles across this with a similar problem, here's what fixed mine:

I had three gauges in my car; a boost and wideband I installed, and a narrowband the previous owner put in. I left the narrowband in for awhile after installing the wideband just to compare, which is how I discovered the primary O2 sensor was toast - gauges read opposite while in boost. I decided to disconnect the narrowband after solving that problem, and presto! No more stalling on warm starts. No idea if that will help anybody else, but I figured I'd update my progress. I've gone about two months now without problems.