stutter

[zamboknee]

I got a new solenoid installed in my tranny in July. Been running fine but recently I've noticed a little 'stutter' while idling.
It does it in Drive and in Neutral/Park.
I timed it to see if there was any set interval for when it would occur but it's very sporadic.
Could this be related to the solenoid? Timing or misfire?
I'm going to take it in but wanted to see if anyone could give me an idea of what to expect.
Thanks
2002 4Runner SR5, 117,000 miles

 

[zamboknee]

Update: It seems the stuttering was because of using low grade gas. Unrelated to solenoid.
When I put high grade gas in, no problems, no stuttering.
After putting the cheap stuff in again (ethanol blend) the stuttering came back.
Is this a fuel injector issue?

 

[zamboknee]

ANY input here would be much appreciated.

 

[zamboknee]

Was driving last night when it did the 'stuttering' thing again. This time I noticed that it draws on the battery as the dash lights dimmed a little bit. Not HUGELY noticeable but definitely happening.