I have a 2000 4Runner 3.4 and lately the CEL has been going on and off and I took it to the parts store and they told me that it was a throttle position sensor which in the past has always been a MAF sensor, but I'm not sure this time. When the CEL is not on and I first start it up and give it a tiny tap of the gas the truck hesitates then revs, which leads me to believe that it truly is the MAF sensor going bad. But once it's been running for a little while it's okay. And when the check engine light comes on it seems to not do it. I'm assuming that's the ECU telling the car to counteract the fact that it's running lean. Has anyone else had any experience with this? Is it my MAF sensor or could it be something else?