Throttle Hesitation/Stumbling

I know there is a lot of information on the topic out there, but everything I’ve read about throttle stumbling seems to have to do with the engine completely stalling or going up and down as the rpms increase. So in my case whenever I blip the throttle, especially when at a low rpm and regardless of if I’m in gear or not, the engine begins to jump as would be expected, then suddenly cuts out. Then, as if it realized it made a mistake, suddenly jumps up to where it should be. But it only ever happens once and then everything is normal throughout the rest of the acceleration and if I slowly lean into the throttle it doesn’t happen. What areas should I check first?

The year of the vehicle?


Sorry 2005 IS300 5 speed with 215k miles

Amount other things, a dead spot in the throttle position sensor could do this.

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Indeed. If the throttle just cuts out, and it isn’t shuddering or anything, most likely it is a faulty throttle position sensor.

Interesting update, I was checking out a handful of things and decided to see what happened if I unplugged the MAF. Interestingly enough it totally took the stutter out. The only problem is the thing looks brand new and seems to be spotless. Any ideas?

Maybe the MAF is actually broken, even if it doesn’t look like it. That might explain the stuttering,…