9thgenidiot

2012 Civic, 182k miles

I recently had my electronic throttle body cleaned at a shop and it was incredibly gunked up with carbon. The cleaning completely solved a ton of rough idle / acceleration issues I was having.

However ever since it was cleaned I've noticed the car has kind of a "cruise control" effect where it will seem to maintain its speed for a bit when I lift my foot off the pedal, then very very slowly begin to slow down normally. For example, I'll be cruising at 20MPH and will let off the pedal.. the car will seem to just continue to coast at 20MPH for a bit and very slowly slow down to an eventual stop. But it's very noticeable how the speed maintains itself, even going up a slight incline.

When going to Reverse from Park, the same kind of thing happens. I hear my car pick up speed to about 7-9MPH and it coasts in reverse at that speed without ever touching the gas pedal.. so it feels like there is some throttle issue SOMEWHERE..?

Along with this, any time my RPMs go down and hit 1,000, it spikes up to 1,200 and then goes down again. This happens when idling or driving. If I am idling at ~750RPM and rev up to 2,000RPM, as the RPMs drop they spike to 1,200 immediately upon hitting 1,000, then drop normally to the idle rate again.

Typical idle RPM is about 700-800 but occasionally rests around 900RPM.

Does this sound like it could be a leak somewhere? I'm thinking maybe the TB gasket wasn't swapped for a new one and there is a slight vacuum causing the throttle plate to open up?

Thanks

holmesnmanny

If you reused the throttle body gasket then yeah it could have a minuscule tear or leak. Those paper gaskets and even most metal crush ones are designed to be one use only. Sometimes you can get away with reusing them but not always. I would say about 60% of the time you could otherwise be fine reusing them.

vtechsjc

That 2012 civic has a drive by wire throttle body on it. We have had to recalibrate/relearn the throttle position after throttle cleaning on several occasions with them. You'll need to take it to the dealer for that I think.