DidIbreakit

Hi All. I have a 2011 g37xS with some issues. 73k miles.

I recently cleaned my throttle bodies and I think messed something up. Immedietely after cleaning the TB, my butt dyno noticed a loss of power on the test drive.

I noticed when stopped at red lights, the rpms sit around 650 then jump to around 850 and the whole car would kinda vibrate (only happened maybe 10% of stops) . After some research I found TB cleaning might help with this, so I went ahead and did it. It fixed the issue, but I guess did something else also.

I did the procedure following this video ( ) All I removed was the rubber boot directly attached to the TB. I then used a old toothbrush and TB cleaner to clean out most of the gunk, The instructions on the can said to manually move the butterfly valve while spraying into the TB as well, so thats what I did. I also had a rag under to absorb any run off. I'm seeing on other threads that moving the valve is a big NO NO. I'm also seeing people say its fine. Did it on each side then put the rubber boot back on done. The car wouldn't turn over the first time I tried to start it. I waited 5 seconds, tried again and it fired right up. Lastly, I did the 3 idle relearning procedures. Car has started fine 50+ times since.

When I first got the G, flooring it would put me back in my seat and rock my head back a little. Now after cleaning TBs, flooring just kinda pulls me along, I dont think I got used to the power because I noticed right after I cleaned the TBs and have only had the car about 4 months. Even when driving like a grandma, I only get 15.5 - 16 mpg with city driving now, when before I got 18-19.

There is no check engine lights or strange noises while driving. The car is idling perfectly now. Just has much worse MPG and acceleration. It seems slower than usual whether I'm in D, DS, or using paddles.

My theory is spraying directly into the TB flooded the spark plugs with carbon and TB cleaner. The TB cleaner evaporated and now theres carbon all over the plugs, causing bad gas mileage and poor acceleration. I'm not much of a mechanic so I could be wrong. What do you guys think? Just want some second opinions because I don't want to buy the plugs and have nothing changed after.

Thanks!

DidIbreakit

Welp I bought new plugs, gunna get em installed asap by shop. I'll report back if it helps because I can't find anyone with my issue after cleaning the throttle bodies.

IndicaVq

Hey! Looks like I'm running into the same situation, cleaned MAF and TB. Did you happen to find a solution?

hoyshnin

Check for an air leak somewhere between the intakes and the throttle bodies. Sometimes, when reassembling the intake system, something's not tightened up or comes loose and air is introduced into the system and causes symptoms like these.