Hi All,

I'm experiencing erratic idle and acceleration on my 01 MPV. The problem began when I put in a new IAC, with a new gasket. There's no codes or check engine warning light. The problem is worse when it's rainy and damp. Around 30-40 MPH, the engine rpms surge and fall back repeatedly. It's idling okay when it's dry and warm, but on a rainy day, the engine isn't kicking down to idle. Driving is kind of unnerving, it's feeling like it wants to get away from me. Also, and possibly unrelated, something is switching on the cooling fan for less than 30 seconds at a time, preceded by a farting noise coming from the area of the air box. I had cleaned the MAF, but didn't replace. The power brake booster hose is pretty crusty, could be leaking. Any ideas? Thanks...

 

Here's a 27 second video of the farting and switching on of the fan. Nothing really to see, but the sound is absolutely coming from inside the air box. The device making the noise I'm pretty sure is responsible for switching the fan off and on.

You Tube